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Gérard FAURE - DESCRIPTION OF THE SYSTEM OF ASTEROIDS AS OF MAY 20, 2004 |
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( Previous full description on 31-December-03 ) |
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English translation : Richard MILES |
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When I began observing asteroids in 1975, I knew hardly anything about them and data about them was not readily available to the amateur. |
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The research I undertook allowed me to discover their large number (several thousand at that time) and their orbital diversity within the Solar System. |
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It was thrilling to learn that these tiny and mysterious travellers wandered between and across the planets, crossing regions unknown to man. |
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I took an avid interest in them and in observing them as much as possible and learning the most about them. |
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Until the middle of the 1990s, each discovery, especially that of an Earth-Grazer was a notable event, and one could continue to have a good idea of the |
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composition of the minor planets on account of the limited number of new objects discovered annually. |
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When the era of automatic observation began and discoveries were made at an ever increasing rate, it was no longer possible to have a complete |
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knowledge of the structure and above all the composition of these tiny Liliputian worlds. |
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In September 2000, for the Meeting of the internet list of Alphonse Pouplier in the south-east of France, I had prepared an article presenting the asteroids, based |
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largely on numbered objects. |
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I had wanted to carry out a more complete analysis including unnumbered objects and the principal acquired knowledge on these asteroids. |
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This was done at the end of April 2002, in French and English. |
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Two updates followed : one partial one in French in August 2002, then a full and more comprehensive one at the end of 2003, translated into English by Richard Miles. |
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Lastly, for the presentation of this dossier at MACE 2004 ( Meeting on Asteroids and Comets in Europe ) in Frasso Sabino near Rome, I have proceeded to |
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update the data through to 20-May-2004. |
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Always with the help of the very useful spreadsheet Microsoft Excel, my personal and up-to-date library and the very useful MPCORB file from the Minor Planet |
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Center website, I have again spent a large part of my free time preparing, over a total period of 3 weeks, this "Description of the System of Asteroids" |
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in our Solar System to 20-May-2004. |
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214044 minor planets have been taken into account and I have processed, sorted, analysed and reanalysed nearly 3 million items of numerical data. |
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I have also newly drawn on information from dozens of recent professional articles and websites, for which references are given at the end of the analysis. |
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Due to a lack of time, the majority of statistics have not been updated since 2003. |
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For the first version in 2002, difficulties encountered had principally been : |
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Determining definite dynamical families and groupings within the Belt N°1 (notably the Nysa-Hertha, Griqua and Flora ones) |
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Assigning the TNOs to known or suspected families |
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The limiting zones of the variously-determined families and groups based on the orbital elements of the asteroids. |
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Updating the basic files as and when new MPECs (Minor Planet Electronic Circulars) are published. |
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For update at the end of 2003, which comprised numerous new categories, the difficulties were primarily : |
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Understanding and putting in summarised form current knowledge about the taxonomy and surface mineralogy of the minor planets. |
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Taking into account the advances in the knowledge of the structure of the Kuiper Belt. |
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Setting up files automating the various statistics presented in this file. |
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Updating all the precise orbital data for asteroids having often changed over 20 months at the level of tenths or hundreths of astronomical units, |
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sometimes even for definitively-numbered minor planets. |
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I have constructed the first analyses so as to give the largest possible number of readers, even those not fascinated by the asteroids, an accurate picture |
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of the various components making up the World of Minor Planets. |
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The initial pleasure has transformed itself into a very interesting work, requiring much research and allowing me to learn again and always, in spite of |
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the large number of years of reading already done. It is also true that our knowledge about the asteroids is perpetually evolving… |
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As an Observer, I also take advantage of this work, which enables one to spot interesting objects to observe in the future. |
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Finally, certain analyses and statistics allow one to specify the limits and real extent of observational problems, bringing about a better appreciation |
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of planned work, sometimes contradicting previous ideas. |
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Of course, in spite of my attention, some errors or omissions have been made in the production of this work, which is published on the website of AUDE ( Association |
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des Utilisateurs de Détecteurs Electroniques, i.e. "Electronic Detectors Users' Association") , in that part reserved for the Magnitude Alert Project (MAP), jointly |
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managed by "The Minor Planet Section of the ALPO" (Association of Lunar and Planetary Observers) and by AUDE. |
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I would be grateful to you, if the case arises, if you would like to let me know by a message addressed to <gpmfaure@club-internet.fr> since it all adds something |
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useful. Thanks in advance. |
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I want to thank my friend Richard MILES (rmiles@baa.u-net.com), who at the MACE 2003 meeting in Mallorca offered his help for future English translations |
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of this dossier and its updates. |
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His very valuable contribution enables the near-simultaneous publication of the French and English versions, close to the very update of the scientific data included. |
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Lastly, I would like to draw your attention to the very interesting website of the Czech astronomer, Petr Scheirich, which can be found at the address : |
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" http://sajri.astronomy.cz/asteroidgroups/groups.htm " |
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A visit to his webpage "Asteroid Groups" enables, with the help of very fine images and graphics, to visualise many groups with various characteristics complementing |
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the account of the "System of Minor Planets" described below. |
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Good reading ! |
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Gérard Faure |
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Asteroids taken into account |
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Number on 31-Dec-03 |
Number on 20-May-04 |
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The 85117 asteroids definitively numbered by the Minor Planet Center. |
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73636 |
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85117 |
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All other unnumbered asteroids from the MPCORB (MPC) file and/or the various lists on the MPC website |
129966 |
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128919 |
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Certain probable NEAs dating from before 1990 and the possible Apohele 1998 DK36 (various sources) |
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7 |
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The largest Plutino, Pluto |
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1 |
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1 |
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Particularly new discovered objects and notified in MPECs later than the download of the last used MPCORB file |
2684 |
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0 |
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206295 |
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214044 |
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NB: On 31-Dec-03, the MPC possessed 232740 asteroid orbits, of which 203605 were available in the MPCORB database and/or in the lists on the MPC website. |
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Those missing from MPCORB and the MPC lists are those of the most uncertain orbits. The objects concerned are effectively lost for the present. |
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Each day, new asteroids are discovered and orbits improved. |
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This update comprises 7749 minor planets additional to those at the end of 2003 and 58039 more than for the previous update to 28-April-2002. |
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NB: Satellites of asteroids are not counted in addition to the primary asteroid |
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Last remark before getting into the nitty-gritty of the subject: For practical reasons involving Excel (lack of space in certain tables, particular uses of brackets on |
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a French keyboard of a laptop PC, etc…), the official name format of definitively-numbered asteroids involving parentheses has not often been adhered to. |
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TERMS USED IN THE DESCRIPTION OF THE SYSTEM OF ASTEROIDS |
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a |
Semi-major axis of the orbit or the mean distance from the Sun in AU |
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albedo |
Percentage of sunlight that an object reflects from its surface. |
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e |
Defines the degree of ellipticity of the orbit, from 0.0 (Circle) to >1.0 (Hyperbola) |
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family |
A family is formed from asteroids having very similar values of "a", "e" and/or "i" |
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G |
Defines the reflection of sunlight by the asteroid as a function of phase angle |
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group |
A group is formed from asteroids situated in the same region of the Solar System having quite similar values of "a", "e" and/or "i" |
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H |
The brightness in the V-band of an asteroid if at a distance of 1 AU from the Sun and 1 AU from the Earth |
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i |
Inclination of the asteroid orbit from the Ecliptic in degrees |
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gap |
Region of the Solar System devoid of asteroids owing to perturbations by a large planet (in particular resonance zones) |
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orbit |
Path in space followed by a celestial body |
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P |
Time required to complete one revolution of the orbit, in terrestrial years |
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Lagrangian Point |
Stable orbital zone at 60° ahead of or behind the same orbit of a large planet ( zone "L5" westwards and zone "L4" to the east ) |
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q |
Perihelion or point in the orbit closest to the Sun, in AU |
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Q |
Aphelion or point furthest from the Sun, in AU |
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resonance |
The natural frequency of a physical system in the regions where the orbital period of the asteroids are at certain fractions of the |
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period of a large planet. |
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AU |
Astronomical Unit = approximately the Earth-Sun distance = 149 597 870 km. |
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NB: Other orbital elements exist. They are less descriptive but are indispensable for working out positional Ephemerides and the brightness of asteroids in the sky. |
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Examples : The "Longitude of the Ascending Node" of the orbit measured from the Vernal Equinox, the "Mean Anomaly" ( mean motion of the asteroid and the interval of time |
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since the asteroid passed perihelion), "the argument of perihelion" ( angle between the ascending node and the perihelion measured in the direction of the motion ), etc.. |
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System of asteroid identification |
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Currently, new asteroid discoveries are subject to a 4-stage identification procedure, from the discovery to the definitive numbering : |
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In brief, the 4 stages are : |
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Stage 1 : Following discovery, the Discoverer assigns it a provisional designation ( Example : J002E3, P00ACE, SS-291, etc…) |
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Stage 2 : When the existence of the asteroid is confirmed, the MPC assigns it a provisional designation comprising the year of discovery, followed by |
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a letter, which defines the half-month in which the discovery was confirmed, and a second letter, usually accompanied by a number, defining |
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the sequential order of confirmation ; (examples : 1937 UB, 1980 AA, 2000 WR106, 2003 WT42, etc…). |
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Stage 3 : When the orbital elements become certain, the MPC assigns it a definitive number, which is indicated before the provisional designation. |
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Example: (20000) 2000 WR106 |
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Stage 4 : Once definitely numbered, the Discoverer can name it. Example: asteroid (20000) 2000 WR106 has become (20000) Varuna. |
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NB: All asteroids have not followed these naming stages in the past and several provisional designations can be involved for the same object when it has been lost several times. |
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It is therefore, generally, the provisional designation that has yielded the definitive identification that is kept. |
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LARGE PLANETS: Table of Minimum, Mean and Maximum Distances from the Sun |
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q in AU |
a in AU |
a in millions of km |
Q in AU |
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P in years |
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MERCURY |
0.307 |
0.387 |
57.8 |
0.466 |
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0.241 |
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VENUS |
0.718 |
0.723 |
108.1 |
0.728 |
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0.615 |
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EARTH |
0.9833 |
1.000 |
149.5 |
1.0167 |
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1.0 |
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MARS |
1.381 |
1.5236 |
227.9 |
1.6662 |
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1.881 |
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JUPITER |
4.947 |
5.202 |
778.2 |
5.456 |
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11.862 |
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SATURN |
9.030 |
9.578 |
1432.8 |
10.125 |
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29.458 |
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URANUS |
18.171 |
19.129 |
2861.6 |
20.087 |
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84.015 |
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NEPTUNE |
29.683 |
29.955 |
4481.2 |
30.227 |
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164.788 |
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(PLUTO) |
29.620 |
39.496 |
5908.5 |
49.372 |
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247.7 |
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HISTORY of Minor Planets to 20-May-2004 |
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16th Century |
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6 planets known, orbiting around the Sun: |
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Planet Dist. in AU Mean Dist. in millions of km |
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MERCURY 0.39 57.9 |
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VENUS 0.72 108.1 |
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EARTH 1.00 149.6 |
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MARS 1.52 227.9 |
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JUPITER 5.20 777.9 |
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SATURN 9.54 1433.9 |
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1596 |
Johannes KEPLER |
The existence of a planetary body between Mars and Jupiter first mooted |
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(Adaptation of Plato's Theory. Crystalline spheres of Ptolemy on 5 geometric solids |
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each supporting a sphere. One of these solids, the Tetrahedron, must support a sphere |
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comprising a planet between the orbits of Mars and Jupiter.) |
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1766 |
Johannes TITIUS and |
Titius-Bode Law : (n+4)/10 where "n" is an element from the series; 0, 3, 6, 12,... |
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Johann BODE |
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Planet Dist. in AU Titius-Bode Prediction |
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MERCURY 0.39 0.4 |
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VENUS 0.72 0.7 |
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EARTH 1.00 1.0 |
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MARS 1.52 1.6 |
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???? 2.8 |
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JUPITER 5.20 5.2 |
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SATURN 9.54 10.0 |
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There must therefore be a planet between Mars and Jupiter.... |
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1781 |
William HERSCHEL |
Discovery of the Planet URANUS located on average 19.2 AU from the Sun, that is 2.887 billion km. |
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The Titius-Bode Law is again obeyed: 19.2 AU cf. 19.6 AU according to the law. |
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1785 to 1800 |
Baron Von ZACK (Hungary) |
Search for the missing planet and start of the Zodiacal star catalogue in 1800. |
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31-Dec-1800 |
Guiseppe PIAZZI |
Star in Taurus recorded on a chart at Palermo Observatory |
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01-Jan-1801 |
Guiseppe PIAZZI |
Discovery of CERES followed until mid-February 1801. |
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Thanks to calculations of Carl GAUSS, VON ZACH relocates Ceres on 07-Dec-1801 |
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28-Mar-1802 |
Wilhem OLBERS |
OLBERS fortuitously discovers PALLAS, having prepared star charts for observing Ceres. |
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01-Sep-1804 |
Karl HARDING |
Olbers, thinking that Ceres and Pallas are two pieces from the same planet, asks for assistance. |
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Karl HARDING finds JUNO on 01-Sep-1804. |
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29-Mar-1807 |
Wilhem OLBERS |
Wilhem OLBERS finds VESTA on 29-Mar-1807. |
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1815 |
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Search abandoned. The Solar System is thus considered to comprise 11 planets. |
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The word "asteroid" coined by William HERSCHEL in 1802 was used only after 1845. |
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08-Dec-1845 |
Karl HENCKE |
Discovery of ASTRAEA after 15 years of solitary searching. |
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Relaunch of the search for asteroids by the astronomical community, principally by amateurs. |
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23-Sep-1846 |
J.G. GALLE and |
Discovery of NEPTUNE orbiting on average some 29.955 AU from the Sun, that is 4.481 billion km. |
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U.V. LE VERRIER |
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End of 1849 |
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10 asteroids are known. They are from now on called "asteroids" or "minor planets" |
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July 1868 |
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100 asteroids are known. |
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Daniel KIRKWOOD explains the gaps devoid of asteroids at certain average distances from the Sun as a |
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result of the resonant action of Jupiter on the orbits of minor planets in the Asteroid Belt. |
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13-Jun-1873 |
James WATSON |
Discovery of 132 AETHRA which at perihelion reaches the aphelion distance of Mars. |
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End of 1891 |
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322 minor planets have been found, all visually. |
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The record is held by Johann PALISA with 83 discoveries resulting from comparing the observed sky with |
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that star charts extending sometimes to 15th magnitude ! |
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20-Dec1891 |
Max WOLF |
First photographic discovery of an asteroid : 323 BRUCIA |
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13-Aug-1898 |
Gustav WITT |
Discovery of 433 EROS, first Earth-approaching asteroid, reaching 0.13 AU, that is 19.9 million km |
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Start of 1900 |
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452 asteroids are known. Their orbits and their ephemerides are still derived by hand ... |
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Data centres established at Berlin and Kiel. |
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24-Dec-1905 |
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First Photographic Discovery by an amateur Joël H. METCALF ( 581 Tauntonia) Taunton (USA) . |
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22-Feb-1906 |
Max WOLF |
Discovery of 588 ACHILLES , first Trojan orbiting with Jupiter, at a Lagrangian point ( L4 ) |
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20-Oct-1920 |
Walter BAADE |
Discovery of 944 HIDALGO, which at aphelion reaches the vicinity of Saturn, at 9.54 AU. |
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1923 |
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1000 asteroids recorded. |
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19-Feb-1930 |
Clyde TOMBAUGH |
Discovery of PLUTO, the first trans-Neptunian object, orbiting at an average distance of 39.44 AU |
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from the Sun (namely 5,900 billion km), but crossing the orbit of Neptune near perihelion. |
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24-Apr-1932 |
Karl REINMUTH |
Discovery of 1862 APOLLO, first asteroid crossing the orbits of the Earth and Venus. |
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28-Oct-1937 |
Karl REINMUTH |
1937 UB alias "HERMES" passes 733,000 km from the Earth. |
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1947 |
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Minor Planet Center set up by the IAU under the direction of Paul HERGET. |
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Start of the publication, "Ephemerides of Minor Planets" by the Institute of Astronomy, Leningrad |
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26-Jun-1949 |
Walter BAADE |
Discovery of 1566 ICARUS, which approaches some 0.18 AU from the Sun, closer than Mercury. |
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05-Dec-1954 |
G.ABELL |
Recovery of 1954 XA, the first ATEN asteroid orbiting on average closer to the Sun than the Earth. |
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10-Aug-1972 |
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The Earth is skimmed at an altitude of 58 km by the "Montana Bolide" (USA) which returned to space. |
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11-Nov-1977 |
Charles KOWAL |
Discovery of 2060 CHIRON, the first CENTAUR, having an orbit ranging from 8.43 to 18.84 AU ( that is |
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2.8 billion km, not far from Uranus). |
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30-Jun-1978 |
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The Minor Planet Center set up in Cambridge (USA) under the direction of Brian MARSDEN. |
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1989 |
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Start of SPACEWATCH telescope operations on Kitt Peak, searching for asteroids making close approaches to Earth. |
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09-Jan-1992 |
Spacewatch - Kitt Peak |
5145 PHOLUS, new Centaur discovered, situated at 32.2 AU, further than the average distance from the |
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Sun of Neptune. |
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30-Aug-1992 |
D. JEWITT and J. X. LUU |
Discovery of 1992 QB1, first TNO (Trans-Neptunian Object) not crossing the orbit of Neptune and |
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orbiting at an average distance of 43.80 AU, namely 6.55 billion km from the Sun. |
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Sep-1992 |
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First CCD discovery of an asteroid by an amateur: 1992 RA by N.KAWASATO |
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09-Dec-1994 |
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1994 XM1 passes 112000 km from Earth, to date the closest Earth-crosser passage observed telescopically |
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09-Aug-1996 |
Palomar/NEAT and |
Discovery of 1996 PW reaching 528 AU from the Sun, i.e. 79 billion km ! |
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Gareth WILLIAMS of the MPC |
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1997 |
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Start of operation of the first LINEAR telescope (New Mexico) systematically combing the sky |
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Mar-1999 |
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10000 numbered asteroids... Not including Pluto ( following discussions on the the status of this small |
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planet or large asteroid ) |
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29-Jul-2000 |
Cerro Tololo Observatory |
Discovery of 2000 OO67 attaining a distance of 1016 AU from the Sun, that is almost 152 billion km ! |
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Its orbital period around the Sun is 11808 terrestrial years ! |
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28-Nov-2000 |
McMILLAN and LARSEN |
2000 WR106 is discovered by Spacewatch. This is the largest TNO discovered to date ( 900 km diameter ) |
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Jan-2001 |
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The 20,000th asteroid is numbered : 2000 WR106, which becomes (20000) Varuna |
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04-Jun-2002 |
TRUJILLO and BROWN |
A very large TNO (1250 km diameter) 2002 LM60 is detected, visible to amateurs using CCDs. |
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(Palomar/NEAT) |
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Nov-2002 |
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50,000 numbered asteroids !! 2002 LM60 becomes known as (50000) Quaoar |
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11-Feb-2003 |
LINEAR |
2003 CP20 is the first asteroid discovered orbiting entirely within the Earth's orbit. |
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21-Aug-2003 |
Deep Ecliptic Survey team |
Confirmation of discovery of first Neptune-Trojan, 2001 QR322 |
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15-Oct-2003 |
Brian SKIFF |
After 66 years of searching, 1937 UB alias "Hermes" is found once more ! |
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19-Feb-2004 |
(Palomar/NEAT) |
2004 DW is a new TNO apparently larger than (50000) Quaoar, with an orbit of the Pluto type. |
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15-Mar-2004 |
BROWN et al |
Announcement of the discovery of 2003 VB12 ( Sedna ), larger than 2004 DW and orbiting at 509 AU from the Sun ! |
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(Palomar/NEAT) |
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18-Mar-2004 |
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The Aten 2004 FH pulverises the record for closest approach to the Earth, at 0.00033 AU, or 49367 km. |
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05-May-2004 |
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The MPC has 251,002 asteroid orbit identified, of which 85,117 comprise definitively numbered objects. |
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It is estimated that the number of asteroids exceeding 1 km in diameter reaches several million .... |
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The hunt for new asteroids is thus far from over .... |
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SOURCES |
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Ref.G.Faure |
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Michel-Alain Combes |
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Deux siècles de découvertes d'astéroides - L' Astronomie Vol.115 janvier-février 2001 |
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Tom Gehrels |
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History and Future - Asteroids -1979 T.Gehrels |
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<GF:FO> |
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Richard A. Kowalski |
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A Brief History of Minor Planet Research: The importance of the Amateur - Minor Planet |
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Amateur/ProfessionalWorkshop 1999. |
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Minor Planet Center |
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Various data on asteroids ( http://cfa-www.harvard.edu/iau/mpc.html ) |
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- |
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Syuichi Nakano |
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List of the first asteroids discovered by amateurs using CCDs |
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Frederick Pilcher and Jean Meeus |
Tables of Minor Planets 1973 |
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<GF:BK> |
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TABLE OF THE SYSTEM OF MINOR PLANETS AS OF MAY 20, 2004 |
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Total |
Total Identified |
Number |
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GROUPS/FAMILIES |
Orbital |
Characteristics |
Remarks |
Numbered |
as of 20-May-2004 |
Estimated |
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1 to 85117 |
Number |
Date |
> 1 km |
|
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Within the Earth's orbit |
|
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|
0 |
3 |
|
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|
|
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|
VULCANOID |
a < 0.22 AU |
Q < q Mercury |
Family still hypothetical |
0 |
0 |
20-May-04 |
max. 900 |
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APOHELE |
a < 1.00 AU |
Q < 1.00 AU |
Orbit entirely within that of the Earth |
0 |
2 |
20-May-04 |
20 ? |
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1 (uncertain) = 1998 DK36 |
|
+ 1 ? |
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Near Earth Asteroids |
|
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|
339 |
2821 |
20-May-04 |
max.1200 |
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ATEN |
a < 1.00 AU |
Q >1.00 AU |
Aphelion external to q Earth |
16 |
220 |
20-May-04 |
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APOLLO |
|
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|
154 |
1354 |
20-May-04 |
|
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APOLLO 1 |
q < 1.00 AU |
a =1.00 to 1.524 AU |
Crosses the Earth's orbit |
74 |
594 |
20-May-04 |
|
|
APOLLO 2 |
q < 1.00 AU |
a =1.524 to 2.12 AU |
Crosses the Earth's orbit |
48 |
433 |
20-May-04 |
|
|
APOLLO 3 |
q < 1.00 AU |
a = 2.12 to 3.57 AU |
Crosses the Earth's orbit |
32 |
325 |
20-May-04 |
|
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APOLLO 4 |
q < 1.00 AU |
a > 3.57 AU |
Crosses the Earth's orbit |
0 |
2 |
20-May-04 |
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AMOR |
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|
169 |
1241 |
20-May-04 |
|
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AMOR 1 |
q < 1.30 AU |
a =1.00 to 1.524 AU |
Does not cross the Earth's orbit |
22 |
225 |
20-May-04 |
|
|
AMOR 2 |
q < 1.30 AU |
a =1.524 to 2.12 AU |
Does not cross the Earth's orbit |
66 |
422 |
20-May-04 |
|
|
AMOR 3 |
q < 1.30 AU |
a = 2.12 to 3.57 AU |
Does not cross the Earth's orbit |
80 |
588 |
20-May-04 |
|
|
AMOR 4 |
q < 1.30 AU |
a > 3.57 AU |
Does not cross the Earth's orbit |
1 |
6 |
20-May-04 |
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NEA (uncertain) |
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6 |
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Inside Belt N°1 |
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1376 |
6790 |
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MARS-CROSSER |
q = 1.30 to 1.6662 AU |
( a, i and e very varied ) |
Crosses Mars' orbit |
638 |
3387 |
20-May-04 |
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MARS-TROJAN EAST |
a ~ 1.524 AU |
i > 16° |
Lagrangian point L4 of Mars |
0 |
1 ? |
20-May-04 |
Total |
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MARS-TROJAN WEST |
a ~ 1.524 AU |
|
Lagrangian point L5 of Mars |
1 |
4 ? |
|
50 ? |
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HUNGARIA |
a = 1.76 to 2.06 AU |
i = 12° to 36° / e < 0.17 |
Between resonances 1:5 and 1:4 |
736 |
3375 |
20-May-04 |
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Pre-Main-belt Objects |
a = 1.88 to 2.06 AU |
low i |
Hungaria zone |
1 |
23 |
20-May-04 |
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BELT N°1 |
a = 2.10 to 4.02 AU |
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82417 |
201774 |
20-May-04 |
1 000 000 |
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to |
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excl. Griquas, Cybeles, Hildas = |
81680 |
200179 |
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1 400 000 |
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maximum |
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ZONE I (INNER) |
a = 2.065 to 2.501 AU |
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Between resonances 1:4 and 1:3 |
32221 |
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Flora (family?) |
a = 2.12 to 2.27 AU |
e = 0.04 to 0.21 / i < 8° |
Between resonances 1:4 and 2:7 |
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(3021) |
2002 |
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Phocaea (group) |
a = 2.23 to 2.50 AU |
e > 0.1 and i = 18 to 32° |
Between resonances 2:7 and 1:3 |
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(Morbidelli) |
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Vesta (family) |
a = 2.349 to 2.374 AU |
e < 0.16 and i = 5 to 8° |
Between resonances 2:7 and 1:4 |
|
(5575) |
2002 |
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Nysa-Hertha (family?) |
a = 2.41 to 2.50 AU |
e = 0.12 to 0.21 / i < 4.3° |
Between resonances 2:7 and 1:5 |
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(6614) |
2002 |
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ZONE II (CENTRAL) |
a = 2.501 to 2.820 AU |
|
Between resonances 1:3 and 2:5 |
27179 |
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Eunomia (family) |
a = 2.563 to 2.670 AU |
e =0.07 to 0.21/ i =11 to 15° |
Between resonances 1:3 and 2:5 |
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(6162) |
2002 |
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ZONE III (OUTER) |
a = 2.825 to 3.279 AU |
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Between resonances 2:5 and 1:2 |
22280 |
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Koronis (family) |
a = 2.828 to 2.939 AU |
e < 0.12 and i < 3.5° |
Between resonances 2:5 and 3:7 |
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(2663) |
2002 |
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Eos (family) |
a = 2.988 to 3.046 AU |
e < 0.13 and i = 8 to 12° |
Between resonances 3:7 and 4:9 |
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(5188) |
2002 |
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Themis (family) |
a = 3.047 to 3.219 AU |
e < 0.22 and i < 3° |
Between resonances 4:9 and 1:2 |
|
(2739) |
2002 |
|
|
Hygiea (family) |
a = 3.108 to 3.217 AU |
low "i" and moderate "e" |
Between resonances 4:9 and 1:3 |
|
(1703) |
2002 |
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Griqua ( Group ? ) |
a = 3.20 to 3.35 AU |
e > 0.35 and i > 17° |
In resonance 1:2 with Jupiter |
5 |
20 |
20-May-04 |
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CYBELE |
a = 3.28 to 3.67 AU |
e < 0.35 and i < 26° |
Between resonances 1:2 and 3:5 |
357 |
702 |
20-May-04 |
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HILDA |
a = 3.74 to 4.02 AU |
quite high e and i < 26° |
In resonance 2:3 with Jupiter |
375 |
873 |
20-May-04 |
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Beyond Belt N°1 |
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6 |
23 |
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THULE |
a = 4.28 AU |
i = 2.3° |
In resonance 3:4 with Jupiter |
1 |
1 |
20-May-04 |
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Internal Jupiter-crosser |
a between 3.6 to 5.0 AU |
high e ; isolated objects |
Crossing towards Q the orbit of Jupiter |
5 |
22 |
20-May-04 |
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Jupiter-Trojans |
|
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877 |
1667 |
|
<2 million |
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JUPITER TROJAN EAST |
a = 4.90 to 5.37 AU |
e < 0.30 and i < 40° |
Lagrangian point L4 of Jupiter |
525 |
1039 |
20-May-04 |
|
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JUPITER TROJAN WEST |
a = 4.96 to 5.36 AU |
e < 0.28 and i < 44° |
Lagrangian point L5 of Jupiter |
352 |
628 |
20-May-04 |
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Beyond Jupiter |
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21 |
79 |
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External Jupiter-crosser |
a > 5.1 AU |
q < 5.1 AU and high e |
Crossing towards q the orbit of Jupiter |
5 |
25 |
20-May-04 |
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CENTAUR |
a = 5.5 to 29 AU |
q > 5.2 AU / i < 35° / high e |
"a" between Jupiter and Neptune |
16 |
53 |
20-May-04 |
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NEPTUNE-TROJAN EAST |
a = 30.1 AU |
e = 0.02 and i = 1.3° |
Lagrangian point L4 of Neptune |
0 |
1 |
20-May-04 |
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NEPTUNE-TROJAN WEST |
a ~ 30 AU |
|
Lagrangian point L5 of Neptune |
0 |
0 |
20-May-04 |
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KUIPER BELT |
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( Discoverable if q < 52 AU ) |
81 |
887 |
20-May-04 |
millions ? |
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KBO Inner I |
a = 30 to 35 AU |
high e / q close to Uranus |
q governed by Uranus ? |
3 |
9 |
20-May-04 |
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KBO 5:4 |
a = 35.0 AU |
q < or = Q Neptune; i ~ 20° |
Resonance 5:4 with Neptune |
1 |
3 |
20-May-04 |
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KBO Inner II |
a= 36 to 38 AU |
e<0.07-0.13 / q >Q Neptune |
Inner Belt + Resonance 4:3 with N. |
6 |
18 |
20-May-04 |
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PLUTON+CHARON |
a = 39.496 AU |
q < Q Neptune |
Resonance 3:2 with Neptune |
0 |
1 |
20-May-04 |
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PLUTINO |
a ~ 39.5 AU |
q near Q Neptune; i ~ 20° |
Resonance 3:2 with Neptune |
20 |
152 |
20-May-04 |
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CUBEWANO |
a = 40 to 47 AU |
q >38 AU ; low "i" et "e" |
( = Classical KBO ) |
27 |
450 |
20-May-04 |
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KBO 5:3 |
a = 42.2 AU |
high "e" |
Resonance 5:3 with Neptune |
2 |
7 |
20-May-04 |
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( TNO uncertain ) |
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TNO with"a"+"e" unknown |
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141 |
20-May-04 |
|
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KBO 7:4 |
a = 43.9 AU |
e > 0.2 |
Resonance 7:4 with Neptune |
1 |
5 |
20-May-04 |
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KBO 2:1 |
a ~48 AU |
high "e" > 0.3 |
Resonance 2:1 with Neptune |
2 |
10 |
20-May-04 |
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Scattered Disk Object |
a > 48 AU ? |
q < 40 AU and high "e" |
( = SKBO ) ; q governed by Neptune |
13 |
80 |
20-May-04 |
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KBO 5:2 |
a ~ 55 AU |
very high "e" > 0.4 |
Resonance 5:2 with Neptune |
5 |
9 |
20-May-04 |
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Extended Scattered Disk |
a > 48 AU ? |
q > 40 AU and high "e" |
Existence still hypothetical |
1 |
2 |
20-May-04 |
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OORT CLOUD |
a > 2000 AU ? |
e > 0.9 and very large "Q" |
a ~ 2000 to 10000 AU ? |
0 |
0 |
20-May-04 |
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( 5 to 10 |
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85117 |
214044 |
20-May-04 |
million ? ) |
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Remarks: |
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The assignment of each asteroid to a group is made following the official classifications : |
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*Majority from the position of their orbit relative to that of the Earth or of Mars, until and including the Mars-crossers, not taking into account their |
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semi-major axis. |
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*For distant objects, it is the position of their orbit relative to Jupiter and/or Neptune depending which dominates. |
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*I have classed Earth-crossers on the basis of the Earth's semi-major axis being equal to 1.000 AU, without taking into account the annual evolution of the Earth's orbit |
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between 0.983 and 1.017 AU. In that, I have followed the rule employed by the Minor Planet Center. |
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I have not departed from the official nomenclature except for those types of object which are more or less unclassified at present : |
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*In the absence of a definitive nomenclature for those asteroids with orbits internal to that of the Earth, I have kept the designation "Apohele" which permits having a |
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fourth name for the 4th type of Earth-crosser orbit in addition to the Aten, Amor and Apollo. |
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Besides, Apohele allows one to adhere to the naming series based on the letter "A" for Earth-crossers. |
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Some minor planets of low inclination and eccentricity, located in the Hungaria zone, have nearly the orbital characteristics of the nearby Objects located in the inner edge |
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of the Belt N°1. I have called them "Pre-Main-belt Objects". |
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*Asteroids situated in the largely empty zones between the Hildas and Jupiter and crossing the Jovian orbit are called "Internal Jupiter-crossers". |
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*Unclassified asteroids beyond Jupiter, but crossing its orbit, have been named "External Jupiter-crossers". |
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*For the inner part of the Trans-Neptunian zone, I have split the present TNOs into "KBO Inner I" and "KBO Inner II", separated by the 5:4 resonance. |
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NB: The limiting zones of the families and groups within the Belt N°1 are based on the known limits for members clearly named in astronomical articles. |
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Evolution of the total numbers since the end of April 2002 |
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Groups |
end-April 2002 |
To 20 May 2004 |
Last update by the MPC |
Increase in 25 months |
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Vulcanoids |
0 |
0 |
20-May-2004 |
0 |
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Apohele |
1 ? |
3? |
20-May-2004 |
1 |
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Atens |
145 |
220 |
20-May-2004 |
75 |
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Apollos |
874 |
1354 |
20-May-2004 |
480 |
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Amors |
854 |
1251 |
20-May-2004 |
397 |
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Mars-crossers |
2396 |
3387 |
20-May-2004 |
991 |
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Mars-Trojans |
6 |
5 ? |
20-May-2004 |
1 |
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Hungarias |
2227 |
3375 |
20-May-2004 |
1148 |
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Belt N°1 ( excl. C and H ) |
146442 |
200179 |
20-May-2004 |
53737 |
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Cybeles |
509 |
702 |
20-May-2004 |
193 |
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Hildas |
568 |
873 |
20-May-2004 |
305 |
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Jupiter-Trojans West |
520 |
628 |
20-May-2004 |
108 |
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Jupiter-Trojans East |
787 |
1039 |
20-May-2004 |
252 |
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Thule + Jupiter-Crossers |
31 |
48 |
20-May-2004 |
17 |
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Centaurs + Neptune-Troj. |
34 |
54 |
20-May-2004 |
20 |
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Internal KBO to CKBO |
531 |
796 |
20-May-2004 |
265 |
|
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SDO |
74 |
89 |
20-May-2004 |
15 |
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ESDO |
1 |
2 |
20-May-2004 |
1 |
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Oort |
0 |
0 |
20-May-2004 |
0 |
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Other Names of families and of groups of Minor Planets |
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Alinda |
Asteroid undergoing libration in the 1:3 gap ( "a" ~ 2.5 AU, in the1:3 resonance with Jupiter ) |
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CKBO |
Second name for asteroids in the Kuiper belt, situated near 42 AU and with a low eccentricity, not crossing the orbit of Neptune. |
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Damocloid |
Group derived from the Oort group of objects, with large "e", "i" and "a" reaching the interior part of the Solar System, often with "i" >90° |
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EGA |
Asteroid which passes closer than 0.100 AU to the Earth's orbit |
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Earth-Grazer |
Old name frequently used prior to that of "NEA". |
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Earth-crosser |
An asteroid crossing the orbit of the Earth ( strictly Apollos or Atens ). |
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Griqua |
Object on the outer edge of the Belt N°1, near 3.27 AU, with "i" > 17° and e > 0.35 (resonance 1:2 with Jupiter) |
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IEO |
Inner Earth Object = Object with orbit completely internal to that of the Earth. Another name for "Apohele" |
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KBO |
Kuiper Belt Object |
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Kubewano |
First name given to asteroids from the Kuiper Belt, located at about 42 AU and with a low eccentricity, not crossing the orbit of Neptune. |
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MBO |
Belt N°1 Object |
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NEA |
Near Earth Asteroid = Asteroid approaching the Earth with q < 1.30 AU |
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NEO |
Near Earth Object = Asteroid or comet approaching the Earth with q < 1.30 AU |
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Oort cloud object |
Damocloid object |
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PHA |
Potentially Hazardous Asteroid ( potentially dangerous ), with H < 22.0 and passing closer than 0.05 AU to the plane of the Ecliptic, at r = 1.0 AU |
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SDO |
Scattered Disk Object = SKBO = Objects scattered from the Kuiper Belt, with "a" > 48 AU and "q" < 40 AU |
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SKBO |
Scattered KBO = SDO = Objects scattered from the Kuiper Belt, with "a" > 48 AU and "q" < 40 AU |
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TNO |
Trans-Neptunian Object = theoretically those situated beyond the orbit of Neptune |
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Vestoid |
Small asteroid making up part of the dynamical family, Vesta, and exhibiting very similar spectral characteristics to those of 4 Vesta. |
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V-type |
Asteroid exhibiting spectral characteristics similar to those of 4 Vesta, without being a member of the Vesta family. |
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Vulcanoid |
Asteroide from a hypothetical belt, located within the orbit of Mercury, from 0.09 AU to 0.21 AU from the Sun. |
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Recent studies indicate the possible existence of 300 to 900 Vulcanoids of more than 1 km diameter ( max. 25 km ), |
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situated at a solar elongation of 4° to 12°, they will be difficult to detect, if they do indeed exist …. |
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Estimates of total asteroid numbers |
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All asteroids with: |
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Diameter > 1.0 km |
> 3 million |
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Diameter > 0.1 km |
billions |
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Earth-crossers: |
( Spaceguard Data ) |
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Diameter > 1.0 km |
2 100 |
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Diameter > 0.5 km |
9 200 |
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Diameter > 0.1 km |
320 000 |
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Diameter, 40 to 100 m |
2 000 000 |
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Diameter > 10 m |
150 000 000 |
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Following more recent estimates, the total number of Earth-crossers with diameter > 1 Km oscillates between 855+/-110 ( Morbidelli et al. en 2001) and 1200 |
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( MPML 23-Jul-02 - Marsden data ). They are expected to comprise; 2% Atens, 23% Amors and 75% Apollos. |
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W.Bottke et al. indicate in their view a composition of; 6% Atens, 32% Amors and 62% Apollos, for NEAs with H < 22. |
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Those NEOs of mag < 18 would number 960 +/-120. |
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The NEA Search Report of NASA of Sep-2003 estimates at 1100 the number of NEAs > 1 km diameter, and at 500,000 those from 50 to 100 m in diameter. |
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Belt N°1: |
( ISO Data ) |
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Diameter > 1.0 km |
1.1 to 1.9 million |
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The most recent estimates based on the Sloan Digital Sky Survey (SDSS) corrects for observing selection bias ( Asteroids III ) and indicates : |
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H < 12.0 = Actual |
2858 |
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H = 12 |
4600 |
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H = 13 |
16000 |
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H = 14 |
50000 |
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H = 15 |
130000 |
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H = 16 |
278000 |
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H = 17 |
518000 |
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Total > 1 km |
1.0 to 1.4 million |
( until H ~ 18.25 ) |
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Kuiper Belt: |
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Diameter > 100 km |
25,000 Plutinos |
( David Jewitt data ) |
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45,000 Cubewanos |
( David Jewitt data ) |
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>10,000 objects in the Extended Scattered Disk ( Data from B.Gladman et al. ) |
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There should be, at the last estimates, around 100,000 TNOs greater than 100 km in diameter between 30 and 50 AU. |
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The recent estimates made at Kitt Peak National Observatory ( MPML 29-May-02 ) arrive at an inventory of 34 objects of the size of Charon and 4 the size of Pluto |
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which should be discoverable amongst the various TNOs. |
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Asteroids having changed family since definitive numbering (1985 to 2003) - Examples |
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1660 Wood |
ex-Mars-Crosser |
Belt N°1 ( Phocaea ) |
q Asteroid at the limit for Q of Mars |
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4015 Wilson-Harrington |
ex-APOLLO 3 |
new AMOR 3 |
q Asteroid at the limit of "a" for the Earth; Comet. |
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4222 Nancita |
ex-Belt N°1 |
new Mars-crosser |
q Asteroid oscillates at the limit for Q of Mars |
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4587 Rees |
ex-Mars-Crosser |
new AMOR 3 |
q Asteroid oscillates at the boundary between the Amors and the Mars-crossers |
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5251 1985 KA |
ex-Belt N°1 ( Phocaea ) |
new Mars-crosser |
q Asteroid oscillates at the limit for Q of Mars |
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6263 1980 PX |
ex-Belt N°1 |
new Mars-crosser |
q Asteroid oscillates at the limit for Q of Mars |
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6454 1991 UG1 |
ex-Belt N°1 |
new Mars-crosser |
q Asteroid oscillates at the limit for Q of Mars |
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6489 Golevka |
ex-Amor 3 |
new APOLLO 3 |
q Asteroid at the limit of "a" for the Earth. |
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7747 Michalowski |
ex-Mars-Crosser |
Belt N°1 |
q Asteroid at the limit for Q of Mars |
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8722 Schirra |
ex-Belt N°1 |
new Mars-crosser |
q Asteroid oscillates at the limit for Q of Mars |
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18751 1999 GO9 |
ex-Belt N°1 |
new Mars-crosser |
q Asteroid oscillates at the limit for Q of Mars |
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30555 2001 OM59 |
ex-Belt N°1 ( Phocaea ) |
new Mars-crosser |
q Asteroid oscillates at the limit for Q of Mars |
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40310 1999 KU4 |
ex-Amor 3 |
new Mars-crosser |
q Asteroid oscillates at the boundary between the Amors and the Mars-crossers |
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Comets numbered as asteroids |
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2060 Chiron |
= |
P/Chiron (95P) |
Discovered as an asteroid in 1977, but considered to exhibit cometary activity in 1988 |
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4015 Wilson-Harrington |
= |
P/Wilson-Harrington (107P) |
Discovered as an asteroid but orbitally linked with a comet by B.Marsden in 1992 |
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7968 Elst-Pizarro |
= |
P/Elst-Pizarro (133P) |
"Comet" of dust with a stellar nucleus, orbiting in the Main Asteroid Belt. |
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NB: The asteroid-comet "Elst-Pizarro" is an exceptional object. This asteroid, from the dynamical "Themis" family, has shown cometary activity in 1996, |
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but was seen as stellar in 1979. The observation of a dust tail was repeated in 2002 thereby eliminating the possibility of a temporary dust tail in 1996, caused by a possible |
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collision. The two outbursts seem however to have been at a similar point in its orbit, perhaps indicating that a small part of the surface of the object, seasonally warmed |
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by the Sun, is responsible for the dust activity. |
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2201 Oljato, having an orbit similar to comet P/Encke has been suspected of gaseous emission similar to that of a comet in 1979 and in 1983. |
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Numerous other asteroids are suspected of being ancient comets, notably those possessing a comet-like orbit ( high eccentricity and inclination, …) |
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Examples: |
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5335 Damocles |
Mars-crosser |
a = 11.831 AU and e = 0.867 |
Halley-type orbit |
H = 13.3 |
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1996 PW |
Oort ? |
a = 265.479 AU and e = 0.990 |
Oort Cloud origin ? |
H = 14.0 |
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Quite a large number of NEAs could be ancient extinct comets, sometimes linked with meteor streams. |
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According to estimates, the percentage of extinct comets amongst the NEOs ranges between 10 and 40%, with the greater likelihood being in the range, 25 to 40%. |
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There are about a dozen Earth-crossers which appear to be linked with meteor streams. |
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3200 Phaeton, an Apollo-type asteroid, is the nucleus of an extinct comet, associated with the Geminid meteors of the 14th December. |
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2101 Adonis and 1995 CS ( H ~ 25 ), having a similar orbit for the last 30,000 years, seem to be associated with 4 active meteor streams located in the |
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constellations of Capricornus and Sagittarius |
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(5496) 1973 NA has been associated with the Quadrantid meteor stream, but it is 2003 EH1 which appears to be the extinct parent body (IAU Circular 8252). |
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Meteor streams appear to contain small bodies several tens of meters in diameter. |
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In 2001, 17 objects from several meters to several tens of meters passed within several million km of the Earth having been found in the proximity of |
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the meteor radiants during the period of activity of the Capricornids, Coma Berenicids, Leonids and Perseids. |
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APOHELE asteroids found or probable as of 20-May-2004 |
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The first definite "Apohele" was discovered on 11-Feb-2003 : |
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Two Apoheles have been discovered to date : |
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2003 CP20 |
H = 16.5 |
a = 0.741 AU |
q = 0.502 AU and Q = 0.9798 AU |
e = 0.322 |
i = 25.61° |
LINEAR |
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2004 JG6 |
H = 18.8 |
a = 0.633 AU |
q = 0.294 AU et Q = 0.9723 AU |
e = 0.633 |
i = 19.215° |
LONEOS |
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These are the first asteroids known, for which the orbit is entirely contained within the Earth's. |
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Venus and Mercury are the only other known bodies in the Solar System orbiting closer to the Sun than the Earth. |
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2004 JG6 even has a semi-major axis smaller than that of Venus ! |
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One other possible Apohele yet to be confirmed has been observed in 1998 : |
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1998 DK36 |
H = 25.0 |
a = 0.693 AU |
q = 0.407 AU and Q = 0.980 AU |
e = 0.413 |
i = 2.03° |
(David THOLEN) |
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Around 20 Apoheles greater than one kilometer in diameter should exist, according to recent estimates. |
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The total number of Apoheles would be equivalent to only 2% of the total NEAs, according to Bottke et al.. |
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An Earth-crosser can evolve dynamically to become an Apohele or IEA, names which have not yet been adopted by the MPC having classed 2003 CP20 and 2004 JG6 as Atens. |
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The terms Amor, Apollo and Aten specifically designate types of orbit close to the Earth: it would be regrettable not to set up a fourth orbital type. |
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NEAR EARTH ASTEROIDS - Various Data |
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In the main, NEAs originate from five sources namely the resonances v6 and 1:3 ( Alindas ), the outer zones of the Belt N°1, Mars-crossers and the |
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family of comets perturbed by Jupiter and originating from the Kuiper Belt. |
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The main sources look to be the dynamical families from the Belt N°1 and the more distant TNOs or from the Oort Cloud. |
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Collisions between asteroids and moreover, the "Yarkovsky Effect" feed resonances capable of injecting new NEAs over several million years into |
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the inner Solar System. |
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Bottke et al. estimate that 61% of NEOs of H < 22 originate from the inner part of the Belt N°1, 24% from the central region, 8% from the outer zone |
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and 6% from the Jupiter family of comets. |
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TheYarkovsky Effect is a very weak thermal impulse when asteroid surfaces are heated by the Sun. The effect particularly affects small asteroids, less than 10 km in diameter. |
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Certain Earth-crossers such as 1996 AJ1 ( Apollo 1 with a = 1.308 AU ) have 8 very close possible approaches (to less than 0.050 AU) to the Inner Planets of the Solar System. |
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Their lifetime is estimated to be very short. |
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The Amor (6178) 1986 DA is in an orbit which permits a collision with Mars. |
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Some NEAs are in resonance with the Earth ; Examples : |
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887 Alinda |
Resonance 3:1 |
'Leader' of a certain number of asteroids in 1:3 resonance with Jupiter, in the 1:3 gap |
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1221 Amor |
Resonance 8:3 |
…and also in 2:9 resonance with Jupiter which with Earth govern the complex secular orbital variations |
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1627 Ivar |
Resonance 11:28 |
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3753 Cruithne |
Resonance 1:1 |
Horseshoe orbit ("a" always between 0.997 and 1.003 AU with a cyclic variation in its orbital elements of 770 years) |
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NB: Other Earth-crossers could become "co-orbiters" to the Earth in the future, such as: 10563 Izhdubar, 3362 Khufu and 1994 TF2. |
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There could however be small asteroids (H > 20) in 1:1 resonance with the Earth. Very faint and dispersed across the sky, they would be very difficult to detect. |
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2002 AA29 ( a 100-m diameter asteroid ) travels along an orbit similar to that of the Earth, and has even been a satellite of the Earth in the past (around 550 AD |
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lasting 50 years). It will do so anew in 2600 and 3880 AD ! |
a = 0.9975 AU / e = 0.012 / i = 10.74° / H = 24.3 |
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Furthermore, certain asteroids such as 1991 VG and 2000 SG344 could be remnants from space vehicle launches, owing to the very strong resemblance of their orbital |
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elements to those of the Earth. The only definite case to date is J002E3 ( discovered by the amateur Bill Yeung ), which must be the third stage of the Saturn V rocket |
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from the launch of the Apollo 12 mission in 1970. Other data are available at the web address: "http://www.projectpluto.com/probes.htm" |
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NEAs having common origins (a, e, i, related) |
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trio |
433 Eros |
1943 Anteros |
1991 JR |
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pair |
1566 Icarus |
5786 Talos |
( pieces from a broken-up parent comet ? ) |
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pair |
1620 Geographos |
10115 1972 SK |
( Asteroid pair, non-cometary origin ) |
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pair |
2101 Adonis |
1995 CS |
Linked with 4 active meteor streams => Joint cometary origin |
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pair |
4015 Wolf-Harrington |
1992 UY4 |
( pieces from a broken-up parent comet ? ) |
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pair |
6318 Cronkite |
6322 1991 CQ |
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pair |
1989 UP |
1989 VB |
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pair |
2201 Oljato |
P/Encke |
( fragments from an hypothetical Centaur named HEPHAISTOS ? ) |
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NB: 2212 Hephaistos and 5143 Heracles could be fragments from an enormous Centaur which ventured into the Inner Solar System following a decrease |
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in its semi-major axis. It would have given birth to numerous NEAs or comets of which P/Encke is one, with "e" ~ 0.70-0.85 and low "i" (between 0 and 12°). |
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Nearly thirty NEAs belonging to this group could be found. |
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Examples of NEAs and numbered Mars-crossers of the type "Alinda" (i.e. "a" ~ 2.501 AU, in the 1:3 resonance zone with Jupiter) |
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887 Alinda |
a = 2.485 AU |
Amor 3 |
Type V = Fragment of Vesta ? |
Resonance 4:1 with Earth |
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2608 Seneca |
a = 2.503 AU |
Amor 3 |
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4179 Toutatis |
a = 2.511 AU |
Apollo 3 |
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6318 Conkrite |
a = 2.508 AU |
Mars-crosser |
q =1.341 AU |
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6322 1991 CQ |
a = 2.515 AU |
Mars-crosser |
q =1.324 AU |
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6489 Golevka |
a = 2.498 AU |
Apollo 3 |
Type V = Fragment of Vesta ? |
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6491 1991 OA |
a = 2.502 AU |
Amor 3 |
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7092 Cadmus |
a = 2.523 AU |
Apollo 3 |
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13551 1992 FL1 |
a = 2.527 AU |
Mars-crosser |
q =1.459 AU |
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19356 1997 GH3 |
a = 2.492 AU |
Amor 3 |
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NEAs in resonance with Jupiter - Examples: |
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1221 Amor |
Resonance 2:9 |
a = 1.919 AU |
Amor 1 |
P = 2.659 years |
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6178 1986 DA |
Resonance 2:5 |
a = 2.809 AU |
Amor 3 |
P = 4.707 years |
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8567 1996 HW1 |
Resonance 1:4 |
a = 2.047 AU |
Amor 2 |
P = 2.929 years |
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NEAs of Type 4 ( a > 3.57 AU beyond the Belt N°1 ) |
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2003 WE42 |
Amor 4 |
a = 3.630 AU and e = 0.696 |
q = 1.101 AU and Q = 6.159 AU |
H = 18.2 |
i = 34.9° |
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2001 XQ |
Amor 4 |
a = 3.641 AU and e = 0.713 |
q = 1.043 AU and Q = 6.239 AU |
H = 19.5 |
i = 28.99° |
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1982 YA |
Amor 4 |
a = 3.707 AU and e = 0.697 |
q = 1.123 AU and Q = 6.291 AU |
H = 16.5 |
i = 34.60° |
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1997 SE5 |
Amor 4 |
a = 3.730 AU and e = 0.666 |
q = 1.244 AU and Q = 6.215 AU |
H = 14.8 |
i = 2.60° |
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2002 RN38 |
Amor 4 |
a = 3.799 AU and e = 0.674 |
q = 1.235 AU and Q = 6.362 AU |
H = 17.3 |
i = 3.84° |
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5025 P-L |
Apollo 4 |
a = 4.201 AU and e = 0.895 |
q = 0.439 AU and Q = 7.962 AU |
H = 15.9 |
i = 6.20° |
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3552 Don Quixote |
Amor 4 |
a = 4.232 AU and e = 0.712 |
q = 1.216 AU and Q = 7.248 AU |
H = 13.0 |
i = 30.8° |
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1999 XS35 |
Apollo 4 |
a = 7.945 AU and e = 0.946 |
q = 0.421AU and Q = 15.468 AU |
H = 17.2 |
i = 19.4° |
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The largest NEAs and their closest-approach distances to the Earth |
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NEA |
Magnitude H |
Diameter in km |
Type of object |
Closest Approach |
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1036 Ganymed |
9.45 |
39 |
Amor 3 |
0.341 AU |
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433 Eros |
11.16 |
33 x 13 x 13 |
Amor 1 |
0.124 AU |
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4954 Eric |
12.6 |
12 |
Amor 2 |
0.194 AU |
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1866 Sisyphus |
13.0 |
8 |
Apollo 2 |
0.102 AU |
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3552 Don Quixote |
13.0 |
19 (very low albedo) |
Amor 4 |
0.301 AU |
( Extinct comet ? ) |
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Frequency of passage by Earth-crossers close to the Earth |
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1 Earth-crosser 400 meters in size passes every 50 years at less than twice the Earth-Moon distance. ( MPML 03-Sep-02 ) |
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1 or 2 Earth-crossers of 100 meters diameter pass by closer than the Moon each year ( Jim Scotti, MPML 24-Jun-02 ) |
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NB: For the 'Earth-crossing' Comets, 180 of them of more than 1 km diameter cross the Earth's orbit each century (Spaceguard data ). |
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Some 2,400 or more 'lilliputians' of around 10 meters diameter pass closer than the Earth-Moon distance each year. |
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Very few of them are observed, as they reach magnitude 14 within 200,000 km of the Earth. They shift very quickly across the sky and are bright for only a few hours. |
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For example, the large rock named 2003 XJ7 of H mag = 26.5 (~30 m) reached mag 13.4 on 06-Dec-03 at 0.0010 AU from the Earth, yet it only spent 8 hours when |
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it was brighter than magnitude 16.0, passing from an RA and Dec of 05h 41m and +45°, to 09h 36m and -67° ! |
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From future predictions, it should be noted that 2000 WO107 ( H = 19.4 with diameter ~ 610 m ) could reach magnitude V + 5.0 in December 2140 ! |
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Collisional frequency of NEAs with the Earth |
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These vary in the time and depend on the source of the estimates : |
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In 1979, Shoemaker estimated one collision of an object of 100 m diameter every 2,000 to 12,000 years or so. |
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20 to 40% of NEAs might be expected to collide with the Earth at some time in the future (Estimates: Wetherhill, 1979, and Shoemaker et al, 1990) |
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From 1975 to 1992, American spy satellites registered 136 explosions of mini-asteroids ranging from a few meters to 10 meters across in the atmosphere, even |
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though the instrumentation was only able to detect 10% of the explosions statistically-speaking. |
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A.Morbidelli et al. in 2001 estimated one collision with an Earth-crosser of H = 20.6 every 63,000 +/- 8,000 years. NEAs discovered to date only represent about 18% |
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of the potential impactors. 82% of them ( excl. Oort objects ) remain to be discovered … |
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Energy released |
Impact interval |
H equivalent |
% of impactors yet to be discovered |
Diameter |
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1000 megatonnes |
63,000 +/- 8,000 yr |
20.63 |
82 |
277 m |
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10,000 megatonnes |
240,000 +/- 30,000 yr |
18.97 |
63 |
597 m |
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100,000 megatonnes |
925,000 +/- 121,000 yr |
17.3 |
51 |
1287 m |
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1 impact of an NEA 50 meters in size occurs every century on Earth ( Jim Scotti, MPML 24-Jun-02 ). |
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2 impacts of an NEA some 100 meters in size occur every 1000 to 2000 years on Earth ( Jim Scotti, MPML 24-Jun-02 ). |
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In August 2003, some English and Russian researchers estimated that one body > 200 m in diameter would hit the surface every 160,000 years. |
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Their results relied on a study of the characteristic behaviour of the impactor during its travel through the atmosphere. |
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The NEA Search Report of NASA of September 2003 indicated an impact frequency of 1 object of 50-100 m every 1,000 years and of 1 object of 1 km |
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size every 500,000 years. |
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The same month, J.Scott of MIT announced in his view that one collision takes place with a 50-meter body every 2,000 to 3,000 years, and every 600,000 |
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years for a body 1 km in diameter. |
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These results come from statistical analyses, which are in effect dependent on the magnitudes H and albedos of Earth-crossers, and also on the rate of formation |
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of craters in the lunar seas. |
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For dormant comets of the "Halley" type and those dormant for a long period, the collisional probability ( 2002 ) is respectively once every 370 and 780 million years. |
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On the 16th March 2880, (29075) 1950 DA has a 1 "chance" in 300 of entering into a collision with the Earth, according to the known stable orbital elements. |
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It should also be pointed out that currently, there are about 50,000 meteorites which fall to earth each year (MPML 24-Sep-02). |
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The oldest NEAs lost from 20 years ago or more |
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5025 P-L |
Apollo 4 |
H = 16.9 |
a = 2.255 AU and q = 0.625 AU |
Palomar Leiden Survey in September 1960 |
|
6344 P-L |
Apollo 3 |
H = 21.5 |
a = 2.379 AU and q = 0.949 AU |
Palomar Leiden Survey in September 1961 |
|
1972 RB |
Amor 3 |
H = 19.7 |
a = 2.149 AU and q = 1.105 AU |
Gehrels - 49-day arc |
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1977 VA |
Amor 2 |
H = 19.0 |
a = 1.864 AU and q = 1.130 AU |
E.Helin - 93-day arc |
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1979 QA |
Apollo ? |
? |
a = ? AU and q < 1.0 AU ? |
Palomar |
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1979 QB |
Amor 3 |
H = 17.4 |
a = 2.329 AU and q = 1.296 AU |
E.Helin - 67-day arc |
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1979 XB |
Apollo 3 |
H = 19.0 |
a = 2.262 AU and q = 0.649 AU |
K. S. Russell |
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1980 QA |
NEA ? |
H = ? |
? |
? |
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1981 JD |
NEA ? |
H = ? |
? |
? |
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1982 CA |
NEA ? |
H = ? |
? |
? |
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1982 EA |
NEA ? |
H = ? |
? |
? |
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1982 YA |
Amor 3 |
H = 16.5 |
a = 3.707 AU and q = 1.123 AU |
F. Dossin |
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1983 LB |
Amor 3 |
H = 16.5 |
a = 2.287 AU and q = 1.194 AU |
E. F. Helin, R. S. Dunbar - 56-day arc |
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1983 LC |
Apollo 3 |
H = 19.0 |
a = 2.632 AU and q = 0.766 AU |
E. F. Helin, R. S. Dunbar |
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1983 SN |
NEA ? |
H = ? |
? |
? |
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1983 VA |
Apollo 3 |
H = 16.5 |
a = 2.609 AU and q = 0.800 AU |
IRAS Satellite - 189-day arc |
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The oldest lost NEAs recovered since 2000 |
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719 Albert |
Amor 3 |
H = 16.0 |
a = 2.584 AU and q = 1.188 AU |
Found on 03-Oct-1911 |
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= 2000 JW8 |
H = 15.8 |
a = 2.637 AU and q = 1.184 AU |
recovered on 01-May-2000 |
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1937 UB Hermes |
Apollo 2 |
H = 18.0 |
a = 1.639 AU and q = 0.616 AU |
observed in 1937 (4-day arc) |
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(69230) |
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H = 17.5 |
a = 1.654 AU and q = 0.621 AU |
recovered on 15-Oct-2003 |
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1950 DA |
Apollo 2 |
H = 15.9 |
a = 1.683 AU and q = 0.838 AU |
observed in 1950 (17-day arc) |
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(29075) |
= 2000 YK66 |
H = 17.0 |
a = 1.699 AU and q = 0.837 AU |
recovered on 31-Dec-2000 |
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1954 XA |
Aten |
H = 18.5 |
a = 0.687 AU and q = 0.261 AU |
1st Aten, observed in 1954 (6-day arc) |
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= 2003 UC20 |
H = 19.2 |
a = 0.781 AU and q = 0.517 AU |
recovered on 21-Oct-2003 |
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4788 P-L |
Amor 3 |
H = 16.9 |
a = 2.612 AU and q = 1.153 AU |
Palomar Leiden Survey of September 1960 |
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= 2003 SV84 |
H = 16.7 |
a = 2.629 AU and q = 1.155 AU |
recovered on 20-Sep-2003 |
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1978 CA |
Apollo 1 |
H = 18.0 |
a = 1.125 AU and q = 0.883 AU |
observed for 32 jours in 1978 |
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H = 17.1 |
a = 1.123 AU and q = 0.883 AU |
recovered on 11-Jan-2003 |
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1975 XA |
Apollo 3 |
H = ? |
a = ? AU et q < 1.0 AU ? |
Wroblewsky - Mag.11 seen - December 1975 |
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= 2004 JN13 |
H = 14.6 |
a = 2,868 AU et q = 0,867 AU |
recovered on 23-Apr-2004 |
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MARS-CROSSERS with large "a" and "e" |
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Mars-crossers are probably produced by various resonances caused by Jupiter ( resonances v6 or 3:1 for example ), Mars and also by the combined |
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pair of Jupiter-Saturn. |
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These resonances slowly increase the eccentricities of the asteroids in the Belt N°1 until their perihelia reach the orbit of Mars, |
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The Mars-crosser population also evolves as a function of the variations in the eccentricity of Mars itself ( 0.01 to 0.12 ) over 2 million years. |
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Thus objects having a q ~ 1.6 AU to 1.78 AU are able to cyclically become Mars-crossers. |
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Certain asteroids such as 5335 Damocles (q = 1.572 AU, a =11.831 AU, Q=22.091 AU) could be called a Mars-crosser (based on q), Jupiter-crosser, |
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Centaur (based on "a"), Saturn-crosser and Uranus-crosser (based on Q). Certain of these are no doubt ancient comets. |
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1997 MD10 is even a Neptune-crosser ! |
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The 3 examples of Mars-crosser having large "a" are: |
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5335 Damocles |
q = 1.572 AU |
a = 11.831 AU |
Q = 22.091 AU |
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1998 WU24 |
q = 1.425 AU |
a = 15.216 AU |
Q = 29.006 AU |
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1997 MD10 |
q = 1.545 AU |
a = 26.581 AU |
Q = 51.618 AU |
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Possible MARS-TROJANS as of 20-May-04 |
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5261 Eureka |
Lagrangian point L5 |
H = 16.1 |
r = 1.425 to 1.622 AU |
First Mars-Trojan discovered in 1990 |
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1998 VF31 |
Lagrangian point L5 |
H = 17.4 |
r = 1.371 to 1.677 AU |
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1999 UJ7 |
Lagrangian point L4 |
H = 17.0 |
r = 1.465 to 1.584 AU |
Doubtful, being at 11H in R.A.of Mars at end-2003 |
2001 DH47 |
Lagrangian point L5 |
H = 19.7 |
r = 1.468 to 1.572 AU |
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2001 FG24 |
Lagrangian point L5 |
H = 21.3 |
r = 1.319 to 1.717 AU |
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2001 FR127 |
Lagrangian point L5 |
H = 19.0 |
r = 1.354 to 1.692 AU |
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2003 SC220 |
Lagrangian point L4 |
H = 20.1 |
r = 1.331 to 1.710 AU |
Doubtful, being at 1.5H in R.A.of Mars at end-2003 |
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NB: The existing list in October 2003 ( prior to the recent case, 2003 SC220 ) has been put in doubt by the MPC who will only reintroduce Mars-Trojans when these objects |
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are confirmed by long-term integrations using good orbits. |
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Nearly 50 or so Mars-Trojans larger than a kilometer could exist. |
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Trojan orbits near to Mars are very stable. |
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Photometric and spectroscopic studies of 3 of the Mars-Trojanshave not revealed any striking similarities between them ( 5261 Eureka, 1998 VF31 and 1997 UJ7 ) |
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There must therefore not have been a common origin for these objects. |
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5261 Eureka and 1998 VF31 are however of a rare mineralogical type ( Sr/A ) not common in Belt N°1. |
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2003 OX7 ( a = 1.5293 AU ) is virtually on the same orbit as Mars, but is not a Mars-Trojan. |
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It made its closest approach to Mars on 4 July 2003 at 0.045 AU, at least for the period 1800-2200 (MPML 02/09/03). |
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MAIN BELT ( or BELT N°1 ) : Data and various remarks |
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One personal remark to begin with : The discovery of many large asteroids of mag H < 4.5 in the Kuiper Belt, and the fact that the First (trans-Martian) Belt only |
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contains 3 may be considered to render the name "Belt N°1" obsolete for this first region of asteroids. |
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The dimensions and divisions of the Belt N°1 are principally due to gravitational perturbations created by Jupiter. |
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The total mass of this trans-Martian belt is estimated to be about 18 X 10^-10 of the solar mass. |
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The zones in resonance with Jupiter are either empty of asteroids (Kirkwood gaps) or stable zones populated by groups of asteroids. |
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More than 99% of primordial asteroids would have been ejected in one million years from the Solar System through perturbations from the larger embryonic planets. |
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TheYarkovsky Effect ( thermally-induced impulse from solar heating of the asteroid surface ) shifts the small objects ( e.g., by 0.04 AU in 100 million years |
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for those of 1 km diameter in the Flora zone ) and contributes to emptying the Solar System of those small asteroids, which enter a resonance zone, |
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finishing by either hitting the Sun or a planet, or by being ejected from the Solar System. |
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With the Yarkovsky Effect, passage close to one of the large asteroids in the Belt can also cause a variation in the orbit of small bodies (0.00075 AU in the case of (1) Ceres). |
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At the end of 1997, those asteroids of mag H < 12.75 , 12.25 and 11.25 (inner, middle and outer regions of the Belt N°1) were considered to have been all found. |
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In 2002, nearly all asteroids from the Belt N°1 up to H = 13.0 had been discovered. |
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At least one third of asteroids from the Belt N°1 are part of asteroid families arising from the fragmentation of larger asteroids following collisions. |
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It is with the aid of the "proper" orbital elements ( a' , e' and sin i ' ) valid over a million years that dynamical families are determined. |
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As time passes, the families become diluted and are less recognisable, following possible collision, and evolution of the proper elements of the asteroids. |
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There may be about 64 groupings of asteroids, of which 32 dynamical families are certain. |
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9 Metis and 113 Amalthea, which exhibit near-identical spectrophotometric data, probably arose from the same parent body of 300 to 600 km size. |
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The most recent family identified is the "Karin" family ( 13 objects with the parent, 832 Karin of 20 km diameter ) which came about as a result of the fragmentation |
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of an asteroid of 27 km in size, 5.8 million years ago. |
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The "Flora" family : |
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It is composed of different sub-families owing to successive collisions arising most probably 500 million years ago ( 900 million years ago at most). |
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Various non-members have already been identified by their different taxonomic type to type S of Flora : 298 Baptistina, 2093 Genichesk, 4278 Harvey, etc.. |
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The parent body of the "Floras" would have had a mass 1.75 times larger than (8) Flora itself with a diameter of 164 km. |
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8 Flora could be the major constituent part from the central region of a large fragmented asteroid. |
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8 Flora (136 km in diameter) and 43 Ariadne (66 km) appear to be the two biggest members of the Floras, the others being hardly 30 km across or less. |
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951 Gaspra, visited by the space probe Galileo, is most likely a fragment from the Flora parent body (same type S and similar orbital elements). |
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With a semi-major axis of 2.256 AU from the Sun and resonances with Jupiter (2:7) and Mars (9:4), there would have been a significant loss of small "Floras" to the |
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Mars-crossers. |
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The "Flora" family would have lost 3% of its members over a 100 million-year period, to the benefit of the Mars-crossers. |
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The Flora and the Phocaea families situated at the inner edge of the Belt N°1 and the v6 resonance would be the main source of the Mars-crossers which after become NEAs. |
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The Phocaea group |
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Located in a region having the 3:1 resonance, their orbits have a large inclination and eccentricity. |
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This group, having particular proper elements, is quite isolated in an 'islet' of stability with limits defined by the action of the main or secular resonances. |
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They never make close approaches to Mars. |
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It is not possible to know whether Phocaeas comprise members of a group having similar orbital elements or members of a family originating from the break-up of a |
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large asteroid. |
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The "Vesta" family : |
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It is composed of 4 Vesta and various small asteroids in similar orbits and of a near-identical reflectance spectral type V, related to Pyroxene and close to that of |
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basaltic HED ( Howardite, Eucrite and Diogenite) meteorites. These small objects are called "Vestoids" and may be pieces of the crust of Vesta, torn away |
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by collision. Together, the Vestoids are believed to be equivalent in volume to a crater 100 km across and 7 km in depth. |
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In 1997, the Hubble Space Telescope (HST) found on the globe of Vesta, a formation which could be the sign of a very large crater. |
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Furthermore, 2579 Spartacus may have a spectral signature similar to the mineral, Olivine, and which could be regarded as a mixed piece of "mantle and |
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crust" of 4 Vesta. |
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1929 Kollaa ( the largest Vestoid with d = 15 km ) could arise similarly from the deep layer of Eucrite from 4 Vesta |
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However, other asteroids also exhibit type V even though they are distant from Vesta. They might be the survivors from another fragmented basaltic asteroid. |
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The Yarkovsky Effect, which can alter the semi-major axis by 0.0001 AU each million years, could be the main cause for the diffusion of the Vesta family. |
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The ejection velocity of the fragments from Vesta or their subsequent acceleration through dynamic evolution could also have directed them close to resonances injecting |
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them into other zones of the Solar System, such as the region of the NEAs. |
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Several examples of non-Vestoid asteroids of type V : |
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809 Lundia ( the biggest non-Vestoid V-type known : d = 9.1 Km ) and 4278 Harvey ( d = 3.3 km ), situated in the Flora zone |
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1459 Magnya of 30 km diameter, situated at a = 3.14 AU in the outer region of the Belt N°1, quite far from 4 Vesta and the only large object of type V in that area. |
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The "Eunomia" family : |
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15 Eunomia represents 70% of the initial mass of the parent body estimated at 284 km in diameter. |
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We know of 110 members larger than 11 km making up the Eunomia family. |
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The "Adeona" family : |
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The age of this family appears to be around 600 million years. It is large having 648 members as of 2002. |
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The "Gefion" family : |
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The age of this family appears to be around 850 million years. Located in the central part of the the Belt N°1 ( a = ~ 2.78 AU ), it comprises 37 known members |
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as of 1995, and 973 members as of 2002, but remains a minor family within the Belt N°1. The asteroid 1 Ceres orbiting in this zone does not make up part of the Gefion family. |
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The "Eos" family : |
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The "Eos" family seems to have arisen from successive collisions between asteroids dating from more than a billion years ago. |
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Several rings of dust have been found by the space probe, IRAS, notably in proximity to the Eos and Themis families. |
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The small members (H>13) of this family will feed the closeby 7:3 resonance, as a result of the Yarkovsky Effect. |
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The "Koronis" family : |
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The "Koronis" family seems to have arisen from successive collisions between asteroids. |
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The age of this family is estimated at 1.5 billion years, based on crater counts on 243 Ida imaged by the space probe Galileo in 1993. |
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The Koronis parent body looks to have been decimated, in that 158 Koronis is estimated to make up only 4% of the initial mass of the parent body of diameter, 119 km. |
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As with the Eos family Eos, the small members ( H>13) of this family will feed the closeby 7:3 resonance, as a result of the Yarkovsky Effect. |
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2953 Vysheslavia, a member of the Koronis family, very close to the outer edge of the 2:5 resonance, could be ejected from the Solar System during the next 10 million years. |
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A recent study of the rotational axes of nearly a dozen members of the Koronis family, 25 to 45 km in size, has shown that the axial alignments fall into two groups of 4 and 6 |
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asteroids, according to whether rotation is prograde or retrograde. |
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In spite of the random primordial distribution of rotational axes following on the initial collision, orbital resonances with Saturn and the Yarkovsky Effect together will have forced |
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an axial realignment for these Koronis objects (the so-called "Slivan state"). |
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Thermal pressure arising diurnally at the asteroid surface could also ( depending on the nature of the shape, surface and rottation of the asteroid) have realigned the |
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axes of the Koronis objects. This long-term effect is named YORP after the name of its discoverers ( Yarkovsky, O'Keefe, Radzievsky and Paddick ) |
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These objects also appear to possess, on average, a larger lightcurve amplitude than other objects from the Belt N°1. |
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The "Themis" family : |
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The family named "Themis" appears to be the result of the break-up of one of the large asteroids ( originally one 380 km in diameter ), some 2 billion years ago. |
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Given that the cometary asteroid 7968 Elst-Pizarro belongs to the "Themis" dynamical family, it could be that the parent body of the "Themis" family had been of mixed |
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nature (part-asteroid, part-comet) such as a large body displaced from the Kuiper Belt. Soon after fragmentation, the numerous pieces must have generated cometary activity. |
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The Griqua group : |
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The asteroids of the Griqua type, located at the limit of the outer sub-belt, near 3.28 AU ( to be found between 3.10 and 3.27 AU ) is only distinguished from the rest of |
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nearby asteroids through their high eccentricities exceeding the (arbitrary ?) limit of 0.35. |
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The Griquas are close to the 1:2 resonance with Jupiter and are protected from planetary interaction by librations about this resonance. |
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Their remaining in this resonance will only last between 1,000 and 1 million years. |
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Some amongst them could be ancient Centaurs. |
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Personal remark : On analysing orbital elements of asteroids situated in the region, a = 3.0 to 3.5 AU, asteroids are found having eccentricities and inclinations, |
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which are weakly spaced out, up until the Griquas and even beyond. Potential Griquas having very high eccentricity find themselves becoming Mars-Crossers. |
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If from the elements of the Griquas themselves it is not possible to differentiate them from other objects in this zone, then they probably do not form a separate group…. |
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Principal resonances with Jupiter ( x:y means: "x" revolutions of Jupiter for "y" revolutions of the asteroid in the same time) |
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Solar Distance |
Resonances |
Kirkwood Gaps |
Groups found: |
P in years |
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a = 1.778 AU |
1:5 |
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2.372 |
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a = 1.908 AU |
2:9 |
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Hungaria |
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a = 2.065 AU |
1:4 |
Resonance v6 |
|
2.965 |
|
|
|
a = 2.256 AU |
2:7 |
(NB: Also corresponds to a 9:4 resonance with Mars) |
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|
|
a = 2.501 AU |
1:3 |
Hestia Gap |
Alinda |
3.954 |
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|
|
a = 2.706 AU |
3:8 |
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|
|
a = 2.825 AU |
2:5 |
Gap |
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|
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a = 2.956 AU |
3:7 |
Gap |
(Between Koronis and Eos families) |
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|
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a = 3.030 AU |
4:9 |
- |
|
|
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a = 3.278 AU |
1:2 |
Hekuba Gap |
Griqua |
5.931 |
|
|
|
a = 3.700 AU |
3:5 |
Gap |
(between Cybeles and Hildas) |
|
|
|
a = 3.969 AU |
2:3 |
- |
Hilda |
7.908 |
|
|
|
a = 4.03 to 4.29 AU |
|
Empty zone |
(between Hildas and Thule) |
|
|
|
a = 4.293 AU |
3:4 |
- |
Thule |
8.896 |
|
|
|
a = 4.29 to 4.90 AU |
|
Empty zone |
(between Thule and Trojans) |
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|
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a = 5.203 AU |
1:1 |
- |
Jupiter-Trojans |
11.862 |
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NB: Other less marked resonances exist such as those of 5:9, 7:4, 5:8, 7:12, etc… |
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All these resonances are so-called "mean motion resonances", which can be misleading in that orbital |
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variations can take place over a short time-scale, of the order of 1000 years. |
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There also exist so-called "secular resonances", connected with the precession of the orbits of bodies interacting. A small body in secular resonance with a large |
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planet sees it's orbit precess in the same manner as a planet's orbit. |
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These secular resonances act over very long periods of over a million years, and produce changes to various orbital elements such as eccentricity and inclination. |
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The v6 secular resonance ( pronounced "nu 6") is a resonance which acts when the rate of precession of longitudes of perihelia of asteroids correspond with those of Saturn. |
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This resonance delineates the inner edge of the Belt N°1. |
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This v6 resonance and that of 3:1 should be the most prolific in generating new NEAs ( 100-160 objects and 40-60 objects with H<18 respectively ). |
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The orbital elements of perturbing planets evolve with time, such that resonances shift in interplanetary space. |
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Resonances are not necessarily empty. The 7:3 resonance actually contains at least 23 asteroids temporarily trapped through the action of the Yarkovsky Effect. |
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They are all small asteroids with the exception of 677 Aaltje (diam. 30 km), perhaps having been pushed into the resonance through the proximity of 1 Ceres. |
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Personal remark: |
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In the various articles on resonances explored, one comes across two types of representation for the same resonances, involving Jupiter. |
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For example: the 3:2 or 2:3 resonance, the 9:2 or 2:9….. |
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To ensure conformance between resonances involving Jupiter and those of the TNO zone, I have therefore standardised on the description of resonances |
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by using the following format : " x revolutions of the major Planet : y revolutions of the Asteroid" |
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Therefore, the "3:5" resonance defines the gap separating the Cybeles and Hildas (3 orbital revolutions of Jupiter for 5 of an object at 3.7 AU) and the resonance "5:3" |
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defines that located in the CKBO zone near 42 AU (5 revolutions of Neptune for 3 of a KBO, hence 5:3) |
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Number of members of the main dynamical families in the Belt N°1, in 1995 and in 2002 |
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Families |
HCM Method 1995 |
WAM Method 1995 |
Estimated number of objects diam. > 5 km |
Morbidelli et al 2002 |
|
|
Flora |
604 |
575 |
709 |
|
3021 |
|
|
|
Nysa / Hertha |
381 |
374 |
? |
|
6614 |
|
|
|
Vesta |
231 |
242 |
402 |
|
5575 |
|
|
|
Ceres/Minerva |
89 |
88 |
? |
|
- |
Family not sure |
|
Maria |
77 |
83 |
654 |
|
1776 |
|
|
|
Adeona |
63 |
67 |
1430 |
|
648 |
|
|
|
Dora |
77 |
79 |
310 |
|
419 |
|
|
|
Eunomia |
439 |
303 |
2748 |
|
6162 |
|
|
|
Hygiea |
103 |
175 |
> 10000 |
|
2663 |
|
|
|
Koronis |
325 |
299 |
729 |
|
2663 |
|
|
|
Eos |
477 |
482 |
4131 |
|
5188 |
|
|
|
Themis |
550 |
517 |
9825 |
|
2739 |
|
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HCM Method |
= Hierarchical Clustering Method (Zappala et al.) |
|
See references |
|
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WAM Method |
= Wavelet Analysis Method (Bendjoya et al.) |
|
See references |
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Morbidelli et al 2002 |
= HCM method used with 106284 minor planets having proper elements ( Knezevic and Milani ) |
|
See references |
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NB: The Nysa zone is populated by various families depending on the author: Nysa, Hertha, Polana, etc… |
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The Hertha and Nysa families are apparently distinguished by a narrow void and a distinct difference in orbital inclination. |
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The "Maria" family is situated on the edge of the strong 3:1 resonance and may furnish the NEA zone with large Earth-crossers. |
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Numbers and H magnitudes of the 4 main members of the principal dynamical families from the asteroid belt : |
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The number and composition of the members of each family differ according to the authors of the studies, the assignment of an asteroid to one or other family is not |
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still 100% certain. From a study by P. Bendjoya, the largest 4 asteroids for sure for each of the principal dynamical families are : |
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Family |
|
|
|
Flora |
8 Flora ( H = 6.49 ) |
43 Ariadne ( H = 7.93 ) |
367 Amicitia ( H = 10.7 ) |
770 Bali ( H = 10.93 ) |
|
|
Nysa + Hertha |
44 Nysa ( H = 7.03 ) |
135 Hertha ( H = 8.23 ) |
1493 Sigrid ( H = 11.99 ) |
1650 Heckmann ( H = 11.56 ) |
|
|
Vesta |
4 Vesta ( H = 3.20 ) |
63 Ausonia ( H = 7.55 ) |
2346 Lilio ( H = 11.9 ) |
2086 Newell ( H = 12.4 ) |
|
|
Maria |
170 Maria ( H = 9.39 ) |
472 Roma ( H = 8.92 ) |
660 Crescentia ( H = 9.14 ) |
714 Ulula ( H = 9.07 ) |
|
|
Eunomia |
15 Eunomia ( H = 5.28 ) |
1275 Cimbria ( H = 10.72 ) |
1329 Eliane ( H = 10.90 ) |
1503 Kuopio ( H = 10.6 ) |
|
|
Koronis |
158 Koronis ( H = 9.27 ) |
167 Urda ( H = 9.24 ) |
208 Lacrimosa ( H = 8.96 ) |
462 Eriphyla ( H = 9.23 ) |
|
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Eos |
221 Eos ( H = 7.67 ) |
579 Sidonia ( H = 7.85 ) |
639 Latona ( H = 8.20 ) |
653 Berenike ( H = 9.18 ) |
|
|
Themis |
24 Themis ( H = 7.08 ) |
62 Erato ( H = 8.76 ) |
90 Antiope ( H = 8.27 ) |
171 Ophelia ( H = 8.31 ) |
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Families of 50 to 100 members and groups known ( in 1995 ) : |
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Phocaea |
a = 2.23 to 2.50 AU |
e > 0.1 and i = 18 to 32° |
grouping of objects from the Inner Belt having high orbital inclination |
|
|
Polana |
a ~ 2.4 AU |
Family of the 'clan', Nysa |
Dynamical family, by the WAM method (102 members known in 1994) |
|
|
Alinda |
a ~ 2.50 AU |
1:3 resonance with Jupiter |
Earth-crossers in libration with Jupiter |
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|
|
Pallas |
a = 2.50 to 2.82 AU |
i = 33 to 38° |
Dynamical family |
(More than 10 members found as of 1994) |
|
Maria |
a =2.526 to 2.591 AU |
e< 0.11 and i < 27° |
Dynamical family |
(74 members found as of 1994) |
|
|
Adeona |
a =2.661 to 2.688 AU |
e< 0.18 and i < 21° |
Dynamical family |
(61 members known for certain by 1994) |
|
Dora |
a =2.763 to 2.813 AU |
e< 0.20 and i < 14° |
Dynamical family |
(75 members known for certain by 1994) |
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|
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NB: The Phocaea group distinguish themselves from other asteroids of the inner Belt N°1 by high inclinations and extend as far as the Mars-crossers, which differ from |
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Phocaeas only by their larger eccentricity to cross the orbit of Mars. |
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The Hilda group |
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Situated in the 2:3 resonance with Jupiter, these asteroids reach aphelion passing in front of the Lagrangian points of Jupiter or in being in opposition with Jupiter, |
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thereby avoiding capture by Jupiter. They pass perihelion facing Jupiter or at 120° of longitude to the giant planet. |
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Thus the Hilda group define a triangle in rotation with Jupiter around the Sun. |
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The Hildas, which have less stable orbits than the Jupiter-Trojans, are expected to be the principal source of cratering of the Galilean satellites. |
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Numbered "internal Jupiter-crossers" with a < a of Jupiter and q > Q of Mars from the 85117 numbered asteroids |
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5164 Mullo |
a = 3.645 AU |
Q = 5.486 AU |
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6144 1994 EQ3 |
a = 4.785 AU |
Q = 6.520 AU |
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20898 Fountainhills |
a = 4.226 AU |
Q = 6.192 AU |
"a" similar to 279 Thule, but "e" and "i" larger |
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32511 2001 NX17 |
a = 5.053 AU |
Q = 7.212 AU |
"a" similar to Trojans West, but the asteroid is far from Point L5 |
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52007 2002 EQ47 |
a = 4.262 AU |
Q = 5.208 AU |
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NB: 37384 2001 WU1 with Q = 4.9295 AU does not cross Jupiter's orbit. |
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JUPITER-TROJANS |
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The Jupiter-Trojans form two populations of isolated objects, at the L4 and L5 Lagrangian points, 60° preceding and following Jupiter in its orbit. |
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They are placed in a very stable zone. |
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Levison et al. have estimated that around 2 million asteroids greater than one kilometer in size could be found at Jupiter's L4 and L5 points. |
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The two Trojan groups situated at the L4 and L5 Lagrangian points are not alike : |
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The L4 group of Trojans-East are larger in number than those of the Trojans-West near Point L5 ( 1039 for Point L4 compared to 628 for Point L5 ). |
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The dynamic families are more numerous for Point L4. |
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Of the larger asteroids, for Point L4 there are : 93 of mag H < 10 compared with only 56 for Point L5. |
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Orbits are more inclined for Point L5 ( 14.7° against 11.4° for Point L4) |
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Trojan Families having more than 10 members arising from collisions: |
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Melenaus |
41 members in 2001 |
Lagrangian Point L4 |
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Epeios |
30 members in 2001 |
Lagrangian Point L4 |
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Podalirius |
22 members in 2001 |
Lagrangian Point L4 |
ex-(4086) 1986 WD |
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Oysseus |
15 members in 2001 |
Lagrangian Point L4 |
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(5119) 1988 RA1 |
23 members in 2001 |
Lagrangian Point L5 |
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On average, collisions would have been more numerous for the Trojans than for the Belt N°1. Consequently, the lightcurve amplitudes are |
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higher on average. |
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Numbered "external Jupiter-crossers" with a > a of Jupiter and q > Q of Mars from the 85117 numbered asteroids |
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944 Hidalgo |
a = 5.746 AU |
q = 1.950 AU |
H = 10.77 |
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15504 1999 RG33 |
a = 9.390 AU |
q = 2.140 AU |
H = 12.1 |
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20461 Dioretsa |
a = 23.759 AU |
q = 2.386 AU |
H = 13.8 |
1999 LD31 |
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37117 2000 VU2 |
a = 6.924 AU |
q = 3.092 AU |
H = 13.2 |
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65407 2002 RP120 |
a = 56.094 AU |
q = 2.473 AU |
H = 12.3 |
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Personal remark: |
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External Jupiter-crossers are not named "Centaurs" but their semi-major axes "a" are similarly situated between Jupiter and Neptune. |
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It is only the Centaurs that have high eccentricity ….. |
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CENTAURS |
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Centaurs have orbits entirely between those of Jupiter and Neptune, in a zone where - due to strong planetary perturbations - the orbits are very |
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chaotic ( lifetimes of less than 10 million years ). |
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The region between Jupiter and Saturn is virtually empty, owing to perturbations from these two giant planets, similarly for the region between Uranus and Neptune. |
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Save for two narrow zones at 7.02 and 7.54 AU and a zone situated between 24 and 27 AU, in which an orbit having very low "e" and "i" can remain stable, only |
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a few resonance zones can be temporarily occupied. |
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The majority of them are situated beyond the orbit of Saturn in a region some 24 to 27 AU from the Sun. |
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Centaurs may be objects derived from the Kuiper Belt in transit towards the inner Solar System, prior to becoming, probably, short-period comets. |
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Some of them stay trapped in resonances linked to a single giant planet during about 1,000 to 10,000 years. |
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Those resonances involving two or three planets at a time can hold them for even longer, more than 100,000 years. |
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There may exist more than 10 million Centaurs greater than 2 km in diameter, of which a hundred may exceed 100 km in diameter. |
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30 to 40% of them do not migrate towards the inner Solar System on cometary orbits |
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These could end up in the region of the Hildas (2:3 resonance with Jupiter) or the Griquas (1:2 resonance with Jupiter). |
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10199 Chariklo is the largest Centaur known to date ( 273 to 302 km in diameter ). Water has been detected on its surface. |
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2060 Chiron, the first Centaur discovered in 1977, is also considered to be cometary ( 95P/Chiron ). |
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Its cometary activity has been recognised since the end of 1987, at which time a surprising increase in its H magnitude was noted. |
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By contrast, the comet C/2000 B4 LINEAR, which is present amongst the Centaurs, has become inactive. If it had been discovered later on then it would have been classed |
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as a Centaur. |
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Other than Chiron, 7 comets are known having Centaur-like orbital characteristics : |
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Comets with Centaure orbits |
q in AU |
a in AU |
|
Q in AU |
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29P/Schwassmann-Wachmann 1 |
5,721 |
5,992 |
|
6,263 |
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39P/Oterma |
|
5,471 |
7,242 |
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9,013 |
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1986XIV-Shoemaker |
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5,457 |
5.473 |
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5.489 |
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P/1997 T3 Carsenty-Nathues |
6,846 |
11,264 |
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15,681 |
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C/2001 T4 NEAT |
|
8,555 |
14,140 |
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19,724 |
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C/2000 B4 LINEAR |
|
6,819 |
18,123 |
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29,428 |
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C/2001 M10 NEAT |
|
5,298 |
26,710 |
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48,123 |
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P/2004 A1 LONEOS |
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5,463 |
7,896 |
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10,330 |
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NEPTUNE-TROJANS |
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If, from strong initial perturbations, Saturn-Trojans and those of Uranus have not been able to survive at the relevant Lagrangian points, those of Neptune |
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must in part have been able to do so. |
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50% of Neptune-Trojans could still remain at the Lagrangian points of Neptune, that is 6,000 to 17,000 objects of mag V = 22 ( d = 110 km ) to V = 25 ( d = 30 km ). |
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One sole Neptune-Trojan is known to date. Discovered in 2001, it has been confirmed during early 2003 : |
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2001 QR322 |
H = 7.3 ( Diam ~ 160 Km ) |
a = 30.1138 AU |
e = 0.025 |
i = 1.327° |
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TRANS-NEPTUNIANS |
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Apart from Pluto found in 1930, the second trans-Neptunian discovered was 1992 QB1 (Asteroid 15760), in January 1992. |
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In spite of observational difficulties, more than 850 TNOs have been discovered as of the end of 2003, but a lot of these have been lost after being followed for a short time. |
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About half of known TNOs have been observed for less than 6 months, which is less than 1% of their orbit, the semi-major axis of which can be in error by dozens of AU ! |
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Even the most well-known TNOs have travelled only a small part of their orbit since their discovery or since identification on old photographic plates. |
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( Pluto 35% of its orbit and 20000 Varuna 16% ). |
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Therefore we still do not have very precise data for the new Kuiper Belt and its members, given that the current means of observation allows one to hardly go beyond 50 AU. |
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Only large objects orbiting or reaching their perihelion within this distance can currently be found. |
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Nevertheless, two large populations have been discerned that is to say the Plutinos having orbits similar to the largest amongst them, Pluto, and a population of objects |
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near 42 AU which does not transect the orbit of Neptune. |
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1992 QB1, an object of the 2nd type, takes its "phonetic" pronunciation from the group called "Cubewanos". |
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This group could be made up of two dynamically-distinct populations, which are differentiated by their inclinations and absolute magnitudes. |
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Over 12 years, the accumulation of discoveries has enabled us to have a better idea of the structure of the Kuiper Belt. |
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There exists a small population of objects for which the semi-major axis is situated between Neptune (a = 30 AU) and the Plutinos (a = 39 AU). |
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It seems that this "inner" zone between 30 and 38 AU must be occupied by those TNOs separated by the 5:4 resonance ( a = 35.0 AU ) |
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Between 30 and 35 AU, there is a population of objects having high eccentricities, which often leads them in the vicinity of the orbit of Uranus near 20 AU. |
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Between 36 and 39 AU, one has principally TNOs with low eccentricities that do not traverse Neptune's orbit and which are close to or in the zone of |
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the 4:3 resonance ( a = 36.6 AU ) |
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In my table, I have therefore named these two zones "KBO Inner I" and "KBO Inner II". |
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Coming now to the Plutinos ( a ~ 39 AU ) and Pluto. They are trapped in the 2:3 resonance with the mean motion of Neptune and often cross the orbit of |
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the planet near their perihelia, but never approaching the planet itself. Pluto never gets nearer than 17 AU to Neptune. |
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A large number of secular and mean motion resonances exist in the zone occupied by TNOs, and these impart a complex structure to the Transneptunian Belt between |
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39 and 41 AU. This region between the Plutinos and 41 AU is not well-populated. |
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The Belt of the Classical Cubewanos", also named "CKBOs" (Classical Kuiper Belt Objects) by Jewitt, occupies a region comprising between a = 40 to 47 AU. |
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The Cubewanos do not intersect the orbit of Neptune and have low eccentricities and inclinations. They are in a very gravitationally-stable part of the Solar System. |
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(50000) Quaoar is the largest TNO presently found in the CKBO belt. |
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A third group of TNOs having high eccentricity with a semi-major axis located beyond 50 AU, has now been found. |
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This is the SDO (Scattered Disk Object) with perihelia less than or close to 40 AU and subject to the influence of Neptune. |
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The origin of this group seems to have been through the external migration of Neptune at the beginning of the Solar System. The orbits of SDOs would have become very elliptical. |
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Only beyond the KBO objects of large eccentricity in the 5:3, 7:4 and 2:1 resonances, we find the beginning of the SDO or SKBO (Scattered Kuiper Belt Objects) zone |
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of which we can currently discover only those objects having large eccentricities with their perihelia within 50 AU. |
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Kuiper-belt objects should be composed of ices of H2O, CO and CO2 together with dust, and should be the origin of the short-period comets. |
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Certain TNOs are susceptible to cometary activity such as the SKBO (29981) 1999 TD10 when close to perihelion. |
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One estimate dating from 2000 put forward the possible existence of 800 million objects greater than 5 km in diameter. |
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Yet, between 90 to 99% of the initial mass in the trans-Neptunian zone would have been lost following perturbations by Neptune and the many collisions between |
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the innumerable initial TNOs. |
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However,a search for small TNOs carried out with the Hubble satellite found only 3 small TNOs of 25 to 45 km in diameter (mag 26 to 28), when 60 small TNOs were expected |
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in the studied zone. This lack of small TNOs has not yet been explained. |
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One more recent estimates made at Kitt Peak National Observatory ( MPML 29-May-02 ) put forward the existence of 34 objects of the size of Charon and 4 of the size of |
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Pluto, which are yet to be discovered in the Kuiper Belt. These as-yet-undiscovered objects would be very faint and therefore distant …. |
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According to a very recent hypothesis of 2003, it could be that the current Kuiper Belt has been formed from objects repelled by Neptune at the time of its outer |
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initial migration, rather than from the presence of a proto-planetary disk beyond 30 AU. |
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Mean-motion resonances of TNOs with Neptune: |
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Main Resonances |
Solar Distance |
Currently numbered TNOs |
Currently unnumbered TNOs |
Remarks |
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Resonance 5:4 |
a ~ 35.1 AU |
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1999 CP133, 2003 FC128, 2002 GW32 |
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Resonance 4:3 |
a ~ 36.6 AU |
(15836) 1995 DA2 |
2000CQ104, 1998 UU43 |
Inner zone of the Kuiper Belt |
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Resonance 7:5 |
a ~ 37.7 AU |
(42355) 2002 XW93 ? |
2002 XW93 ? |
Region empty of TNOs ? |
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Resonance 3:2 |
a ~ 39.4 AU |
Pluton and the Plutinos |
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Plutinos zone |
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Resonance 5:3 |
a ~ 42.1 AU |
(59358) 1999 CL158, (15809) 1994 JS and 2002 VA131, amongst others |
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Resonance 7:4 |
a ~ 43.8 AU |
(60620) 2000 FD8 |
2000 OP67, 1999 KR18 |
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Resonance 9:5 |
a ~ 44.6 AU |
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2000 QM51 ? |
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Resonance 2:1 |
a ~ 47.8 AU |
(40314) 1999 KR76, (20161) 1996 TR66, (26308) 1998 SM165, 1997 SZ10, amongst others |
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Resonance 5:2 |
a ~ 55 AU |
(26375) 1999 DE9, (38084) 1999 HB12, (60621) 2000 FE8, amongst others |
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Resonance 11:2 |
a ~ 92 AU |
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Resonance 15:2 |
a ~ 115 AU |
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The actual or possible presence of TNOs in the resonances 1:1, 5:4, 4:3, 3:2, 5:3, 7:4, 9:5, 2:1 and 5:2 has recently been confirmed on the basis of theoretical calculation. |
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Save for the Neptune-Trojans (resonance 1:1), those TNOs in resonances are all of high orbital eccentricity or inclination. |
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NB: There are several secular resonances present which cross the inner resonances of the Kuiper Belt. |
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PLUTO = Major Planet or big Asteroid ? |
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Pluto is twice as small as the other solid planets located very close to the Sun |
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Pluto crosses the orbit of another Giant Planet and is in a 2:3 resonance with it, and thus remains under its influence. |
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Its diameter is less than that of many natural satellites such as the Moon. |
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Its orbit is similar to those of the very numerous trans-Neptunians "controlled" by Neptune. |
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Its round shape and (likely) internal differentiation already exist for the largest asteroids. |
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Some satellites notably Titan have an atmosphere thicker than that of Pluto. |
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Other asteroids possess their own satellite, such as the Earth-crosser 69230 Hermes, 243 Ida in the Belt N°1, the Kuiper object 1998 WW31, etc.... |
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A comparative table of main data shows the great difference between the inner planets and the three biggest TNOs : |
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EARTH VENUS MARS MERCURY PLUTO SEDNA 2004 DW |
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Mass |
1 0.81 0.11 0.06 0.0017 ? ? |
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Diameter in Km |
12742 12104 6792 4879 2300 1600? 1300? |
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Density in d/cm3 |
5.515 5.24 3.94 5.43 2.05 ? ? |
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Orbit shaped by : |
Sun Sun Sun Sun Neptune Sun Neptune |
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+ Sun + Sun |
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Continuing to include Pluto as one of the Large Planets which shape their own environment seems at present to be a little daring …. |
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There is nothing which distinguishes Pluto from the other Plutinos with the exception of its size as the largest TNO currently known. |
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Some yet-unknown objects in the Kuiper Belt may perhaps also be as big as Pluto ? |
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In comparison to Ceres, which was rightly relegated from its position as a "Planet" after 45 to 50 years during the 19th Century, Pluto in proportion |
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is hardly much bigger than the plutino 2004 DW in relation to what Ceres is towards the other very large asteroids of the Belt N°1. |
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To relegate Pluto from its status as a Major Planet would take nothing away from its title as the largest Plutino nor from the credit of the discoverer, Clyde Tombaugh. |
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One might also claim that there is an injustice at present concerning Giuseppe Piazzi, discoverer of 1 Ceres, the largest main-belt asteroid ... |
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It is still regrettable that an out-moded chauvinism can at present get the upper hand over a scientific fact accepted by the majority of the International |
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Astronomical Community. |
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The inclusion of definitively-numbered objects also allows less room for distorting the statistics, work and analyses done on these objects … |
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The N° 100000, if assigned to Pluto, would allow one at last to honour the largest and most exceptional double asteroid, that is the Pluto-Charon system. |
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EXISTENCE OF A DIFFUSE DISK EXTENDING BEYOND 50 AU ? |
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Beyond 50 AU from the Sun, the Astronomical Community is largely reduced to making suppositions concerning the most distant regions of the Kuiper Belt. |
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The apparent absence of TNOs having near-circular orbits beyond 47 AU could be a sign that a massive body is situated beyond 50 AU. |
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With a quite low eccentricity, it may be in a very inclined orbit, and therefore has not been found to date. |
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This massive body some 2000 to 4000 km in diameter could be orbiting on average some 62 AU from the Sun, with q = 49 AU, Q = 78 AU and e = 0.21. |
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Its visual magnitude would be between +18.5 and +21.5 for the case having an albedo of 0.04, or +16.2 to +19.7 if having a high albedo of 0.3. |
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The outer limit of the Kuiper zone is still not known, but up until 2003 has been considered to be about 200 AU from the Sun. |
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Dust disks around other nearby solar-type stars can extend between 35 AU and 75 AU in the case of 'Epsilon Eridani, being a billion years old, |
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to 1000 AU for very young stars like Beta Pictoris. The residual disk around the Sun should certainly tend in size towards that of Epsilon Eridani. |
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A study in 2001 by B.Gladman et al. looked to prove the existence of an Extended Scattered Disk, which could contain at least 10,000 "SDOs" greater than |
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100 km, and even more than in the SKBO zone, with high "a" and "q" > 40 AU. |
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(48639) 1995 TL8, 2000 CR105, as well as a number of unrecovered KBOs should be members of this Extended Scattered Disk. |
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Those objects observed to date over less than 2% of their orbit have been very difficult to discover and authenticate over time as being members of this Extended Scattered Disk. |
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The massive object named 2003 VB12 ( alias "Sedna" ) discovered in November 2003 could also be a member of this extended diffuse disk |
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2000 CR105 and 2003 VB12 are the only objects currently known orbiting well away from the gravitational influence of Neptune. |
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2003 VB12 is the most massive TNO known after Pluto and is characterised by an elliptical orbit well removed from the major planets. |
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q = 76.067 AU |
a = 509 AU |
Q = 942 AU |
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The origin of its current orbit is not evident, although at present there is a tendency towards the idea of a passing star approaching to about 800 AU of the Sun. |
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This star could have ejected 2003 VB12 and the ESDOs from the TNO zone, soonafter the formation of the Solar System ( A.Morbidelli and H.Levison ) |
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Very distant asteroids with "a" = 100 AU and + ( as of 20/05/04) |
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Objects |
H |
a in AU |
Period in years |
q in AU |
Q in AU |
e |
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1999 RZ215 |
7.8 |
100.319 |
1004.8 |
30.959 |
169.680 |
0.691 |
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(65489) 2003 FX128 |
6.3 |
103.530 |
1053.4 |
17.822 |
189.238 |
0.827 |
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1999 DP8 |
8.9 |
116,000 |
1249.4 |
34.741 |
197,000 |
0.700 |
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1999 CZ118 |
7.9 |
117.151 |
1268.0 |
37.732 |
196.571 |
0.677 |
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1999 RD215 |
7.5 |
121.088 |
1332.5 |
37.598 |
204.578 |
0.689 |
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(54520) 2000 PJ30 |
8.0 |
121.767 |
1343.7 |
28.531 |
215.002 |
0.765 |
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2002 GB32 |
7,4 |
216.909 |
3194.6 |
35.361 |
398.457 |
0,836 |
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(82158) 2001 FP185 |
6,1 |
227.133 |
3423.1 |
34.253 |
412.889 |
0,849 |
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2000 CR105 |
6,1 |
228.582 |
3455.9 |
44.275 |
420.013 |
0,806 |
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1996 PW |
14,0 |
265.479 |
4325,6 |
2.541 |
528.418 |
0,990 |
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2003 VB12 |
1,6 |
509.107 |
11487.2 |
76.066 |
942.147 |
0,850 |
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2000 OO67 |
9,1 |
518.538 |
11807.9 |
20.764 |
1016.312 |
0,959 |
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NB: 1996 PW has a cometary-like orbit; yet it will have been recognised as an asteroid so long as it did not exhibit cometary activity. |
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This was the case for example for 2002 VQ94 ( a = 205 AU ) which has become the comet C/2002 VQ94. |
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Personal comment : If the first 2 of the 12 distant asteroids orbiting at more than 100 AU from the Sun are regarded as being associated with the SDO group between |
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50 AU to 104 AU, there appears to remain 3 concentrations for 9 of the 10 more-distant objects, namely : |
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1) A group of 4 objects between 116 and 122 AU, perhaps linked to the 15:2 resonance with Neptune, located near 115 AU |
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2) 3 objects between 217 and 227 AU : 2002 GB32, 2000 CR105 and (82158) 2001 FP185 |
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3) A pair situated towards 515 AU, made up of 2003 VB12 and 2000 OO67 |
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The successive differences between the SDOs and these 3 concentrations seems to correspond to about 8, 95 and 282 AU, respectively. |
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The only isolated and distant asteroid is the "Damocloid" 1996 PW which has above all a cometary orbit and has a very small diameter. |
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The 65 comets known with a semi-major axis between 104 and 530 AU appear to be related to one or other of these 3 concentrations. |
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Respectively 2, 4 and 1 comets are in the areas of the three groupings of asteroids. |
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La comète orbiting at the same distance than 2003 VB12 and 2000 OO67 is C/1948X Bester, with a = 509.168 AU |
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The orbits of all these very distant objects are still imprecise and so any possible groupings need to be considered tentative at present |
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May be the future discoveries will change the aspect of these actual concentrations. |
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THE OORT CLOUD |
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The inner limit of the Oort Cloud is believed to be located between 2000 and 3000 AU. |
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To date, no asteroid having a semi-major axis of 2000 AU or more has been found. |
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2003 WT42, with a = 5840 AU and P = 158,028 years, would have been aa "Oort" asteroid, if a weak cometary activity had not been detected in January 2004. |
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Its staus has therefore now been changed, having become the comet C/2003 WT42. |
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It has however been noted that its cometary activity is quite feeble for a comet arising from the Oort Cloud. |
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It could therefore instead be an asteroidal body ejected from the inner Solar System very early on in it's formation. |
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Furthermore, it is not impossible that 2003 VB12 and 2000 CR105 could have been in fact ejected from the Oort Cloud, following a close approach by a passing star, |
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which perturbed them causing them to approach the inner Solar System. 2003 VB12 pourrait donc être un membre du "Nuage d'Oort interne". |
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Lastly, there could exist here in the inner Solar System some objects that also could have originated in the Oort Cloud : the Damocloids. |
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The Damocloids : |
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Asteroids having this unofficial name have characteristics including a very high eccentricity and/or a very high orbital inclination, which |
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most probably have their origin in the Oort Cloud. The present list is that of Brian Skiff's, and covers those asteroids having as characteristics : |
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q < 5.2 AU, e > 0.7 and i high and/or retrograde : |
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5335 Damocles |
a = 11.831 AU |
H = 13.3 |
e = 0.867 and i = 62.1° |
q = 1.572 AU |
Q = 22.091 AU |
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(15504) 1999 RG33 |
a = 9.390 AU |
H = 12.1 |
e = 0.772 and i = 34.9° |
q = 2.140 AU |
Q = 16.641 AU |
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20461 Dioretsa |
a = 23.759 AU |
H = 13.8 |
e = 0.899 and i = 160.3° |
q = 2.386 AU |
Q = 45.131 AU |
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(65407) 2002 RP 120 |
a = 56.094 AU |
H = 12.3 |
e = 0.955 and i = 119.1° |
q = 2.473 AU |
Q = 109.714 AU |
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1996 PW |
a = 265.4 AU |
H = 14.0 |
e = 0.990 and i = 29.7° |
q = 2.541 AU |
Q = 528.4 AU |
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1997 MD10 |
a = 26.581 AU |
H = 16.0 |
e = 0.941 and i = 59.0° |
q = 1.545 AU |
Q = 51.618 AU |
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1998 QJ1 |
a = 11.274 AU |
H = 16.5 |
e = 0.812 and i = 23.4° |
q = 2.109 AU |
Q = 20.439 AU |
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1998 WU24 |
a = 15.216 AU |
H = 15.0 |
e = 0.906 and i = 42.5° |
q = 1.425 AU |
Q = 29.006 AU |
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1999 LE31 |
a = 8.128 AU |
H = 12.4 |
e = 0.469 and i = 151.8° |
q = 4.315 AU |
Q = 11.954 AU |
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1999 XS35 |
a = 17.945 AU |
H = 17.2 |
e = 0.946 and i = 19.4° |
q = 0.946 AU |
Q = 34.937 AU |
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2000 AB229 |
a = 53.066 AU |
H = 14.0 |
e = 0.956 and i = 68.7° |
q = 2.297 AU |
Q = 103.8 AU |
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2000 DG8 |
a = 10.804 AU |
H = 13.1 |
e = 0.793 and i = 129.4° |
q = 2.229 AU |
Q = 19.378 AU |
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2000 HE46 |
a = 23.597 AU |
H = 14.8 |
e = 0.900 and i = 158.4° |
q = 2.359 AU |
Q = 44.835 AU |
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2000 KP65 |
a = 88.737 AU |
H = 10.5 |
e = 0.963 and i = 45.6° |
q = 3.274 AU |
Q = 174.2 AU |
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2001 QF6 |
a = 7.248 AU |
H = 15.4 |
e = 0.688 and i = 24.2° |
q = 2.255 AU |
Q = 12.240 AU |
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2003 UY283 |
a = 33.453 AU |
H = 15.3 |
e = 0.895 and i = 18.8° |
q = 3.506 AU |
Q = 63.401 AU |
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Personal remark : This list cannot be exhaustive, even for found objects, as certain Damocloids can have a low inclination. |
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For example, this could be the case for 2004 CM111 ( q = 4.942 AU, a = 33.180 AU, e = 0.851 but with i = 4.7° ) |
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2001 QF6 and 1999 LE31 are under the excentricity required, while the asteroids below are not included : |
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3552 Don Quixote |
a = 4.231 AU |
H = 13.0 |
e = 0.712 et i = 30.8° |
q = 1,215 AU |
Q = 7.247 AU |
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2003 WN188 |
a = 14.567 AU |
H = 14.1 |
e = 0.849 et i = 26.9° |
q = 2,199 AU |
Q = 26.935 AU |
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DATA AND STATISTICS RELATING TO THE MINOR PLANETS |
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Various absolute records as of 20-May-04 from the 214014 minor planets |
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TYPE |
ASTEROID |
RECORD |
ASTEROID GROUP |
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q minimum |
2000 BD19 |
0.0919 AU |
ATEN |
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q maximum |
2003 VB12 |
76.066 UA |
ESDO ? |
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a minimum |
2004 JG6 |
0.6332 UA |
APOHELE |
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a maximum |
2000 OO67 |
518.5 AU |
OORT ? |
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Q minimum |
2004 JG6 |
0.9723 UA |
APOHELE |
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Q maximum |
2000 OO67 |
1016.3 UA |
SDO ? |
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P minimum |
2004 JG6 |
184.4 days |
APOHELE |
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P maximum |
2000 OO67 |
11808 years |
ESDO ? |
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e minimum |
2002 XR24 |
e = 0.0001293 |
BELT N°1 |
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e maximum |
1996 PW |
e = 0.959 |
SDO ? |
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H max known |
2003 SQ222 |
H=30.1 (about 4 meters) |
APOLLO 1 |
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H min - Belt N°1 |
(4) Vesta |
3.20 |
BELT N°1 |
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Largest - Belt N°1 |
(1) Ceres |
933 km (diameter) |
BELT N°1 |
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H min - TNO |
Pluton and 2003 VB12 (Sedna) |
-1.1 and +1.6 |
PLUTINO et ESDO |
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i minimum |
2004 FH |
i = 0.02081° |
ATEN |
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i maximum |
(20461) Dioretsa |
i = 160.3955° |
JUPITER-CROSSER |
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rotation minimum |
2000 DO8 |
Period = 1.3038 min |
APOLLO-3 |
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rotation maximum |
(288) Glauke |
Period = 1200 h |
BELT N°1 |
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V Ampl. minimum |
(1) Ceres |
0.04 magnitude |
BELT N°1 |
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V Ampl. maximum |
1865 Cerberus |
2.10 magnitude |
APOLLO-1 |
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|
Min.Dist.from Earth - seen |
2004 FH |
0.00033 AU ( 49367 Km) |
(18.9/03/2004) ATEN ( H =25.7 ) |
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(as of 20-May-04) |
2003 SQ222 |
0,00056 AU (83774Km) |
(27.9/09/2003) APOLLO-1 ( H = 30,1 ) |
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1994 XM1 |
0,00072 AU (107700Km) |
(09.8/12/1994) APOLLO-2 ( H = 28,0 ) |
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Min.Dist.from Earth - pred. |
2000 SB45 |
0.00142 AU (212400 km) |
(07.8/10/2037) APOLLO 2 ( H = 24.5 ) |
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for the future |
2001 WN5 |
0.00167 AU (249800 km) |
(26.2/06/2028) APOLLO 2 ( H = 18.3 ) |
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(as of 20-May-04) |
1999 AN10 |
0.00265 AU (396000 km) |
(07.3/08/2027) APOLLO 1 ( H = 17.1 ) |
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( prior to 2037 ) |
2003 MK4 |
0.00507 AU (758400 km) |
(03.9/01/2032) APOLLO 1 ( H = 21.0 ) |
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NB: The asteroid observed closest to the Earth was in fact the "Montana Bolide", which in 1972, skimmed the Earth's upper atmosphere reaching a minimum |
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altitude of 58 km, and much of which was consumed before returning to space. |
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Orbit prior to encounter : |
a = 1.661 AU |
e = 0.3904 |
q = 1.0127 AU |
i = 15.22° |
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Amor 2 |
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Orbit after encounter : |
a = 1.471 AU |
e = 0.3633 |
q = 0.9369 AU |
i = 6.92° |
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Apollo 1 |
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NB: The minimum V amplitude is taken from those lightcurves, which we know are complete. |
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Various records by Group as of 31-Dec-03 for the 203614 asteroids and for the 73606 numbered ones only |
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Groups / Limits "a" |
"a" min |
"a" max |
Object "a" min. // Object "a" max. |
Numbered, "a" min. |
Numbered, "a" max. |
|
Apohele |
0.693 AU |
0.741 AU |
2003 CP20 // 1998 DK36 |
- |
- |
- |
- |
|
Aten |
0.642 AU |
0.9988 AU |
(66391) 1999 KW4 // 1998 UP1 |
66391 |
0.642 AU |
3753 |
0.997 AU |
|
Apollo |
1.0006 AU |
17.945 AU |
(54509) 2000 PH5 // 1999 XS35 |
54509 |
1.0006 AU |
14827 |
2.846 AU |
|
Amor |
1.034 AU |
4.232 AU |
1992 JD // (3552) Don Quixote |
66407 |
1.198 AU |
3552 |
4.232 AU |
|
Mars-crosser |
1.390 AU |
26.581 AU |
(1951) Lick // 1997 MD10 |
1951 |
1.390 AU |
5335 |
11.831 AU |
|
Hungaria |
1.768 AU |
2.098 AU |
2002 JA14 // 2002 QZ5 |
45873 |
1.768 AU |
54420 |
2.055 AU |
|
Belt N°1 (a < Cybeles) |
2.0662 AU |
3.2914 AU |
2003 SH241 // 2003 YK69 |
59039 |
2.1009 AU |
11097 |
3.2798 AU |
|
Cybele |
3.283 AU |
3.673 AU |
2003 BS48 // 2003 KB11 |
14871 |
3.284 AU |
13096 |
3.654 AU |
|
Hilda |
3.745 AU |
4.022 AU |
2002 TB96 // 2003 QY103 |
70032 |
3.748 AU |
17305 |
4.019 AU |
|
Jupiter-Trojan East |
4.906 AU |
5.385 AU |
1997 TW2 // 2003 FH103 |
63176 |
5.050 AU |
22049 |
5.367 AU |
|
Jupiter-Trojan West |
4.961 AU |
5.361 AU |
2000 HR24 // (34835) 2001 SZ249 |
24454 |
5.062 AU |
34835 |
5.361 AU |
|
Jupiter-crosser |
3.349 AU |
88.737 AU |
2002 LJ27 // 2000 KP65 |
5164 |
3.645 AU |
65407 |
56.094 AU |
|
Centaur |
7.883 AU |
28.968 AU |
2000 GM137 // 2002 FY36 |
52872 |
8.404 AU |
52975 |
26.209 AU |
|
Inner KBO |
30.229 AU |
38.955 AU |
2001 XA255 // 1998 WV24 |
73480 |
30.743 AU |
42355 |
38.383 AU |
|
Plutino |
38.769 AU |
40.149 AU |
2003 FF128 // 2000 YH2 |
38083 |
39.207 AU |
38628 |
39.607 AU |
|
Cubewano + KBO 2:1 |
40.308 AU |
48.067 AU |
1999 OH4 // (40314) 1999 KR16 |
24835 |
41.804 AU |
40314 |
48.986 AU |
|
SDO |
49.041 AU |
121.767 AU |
2000 AF255 // (54520) 2000 PJ30 |
60608 |
49.996 AU |
54520 |
121.767 AU |
|
Oort ? |
265.480 AU |
518.538 AU |
1996 PW // 2000 OO67 |
- |
- |
- |
- |
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NB: The limits in "a" indicated are established only after the fact that the object's membership of a group is assured. |
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Group / H mag range |
Minimum H |
Maximum H |
Remarks |
|
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|
|
Apohele |
16.5 ( 2003 CP20 ) |
25.0 ( 1998 DK36 ? ) |
|
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|
Aten |
14.5 ( 1999 HF1 ) |
29.1 ( 2003 SW130 ) |
|
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|
Apollo |
13.0 ( 1866 Sisyphus ) |
30.1 ( 2003 SQ222 ) |
|
|
|
Amor |
9.45 ( 1036 Ganymed ) |
27.6 ( 2001 UD18 ) |
only one large Amor 1 : 433 Eros ( H = 11.2 ), followed by 1943 Anteros ( H = 15.8 ) |
|
Mars-crosser |
9.38 ( 132 Aethra ) |
22.8 ( 2002 NU16 ) |
|
|
|
Mars-Trojan |
16.1 ( 5261 Eureka ? ) |
21.3 ( 2001 FG24 ? ) |
|
|
|
Hungaria |
11.21 ( 434 Hungaria ) |
20.6 ( 2003 HE2 ) |
2003 HE2 : q = 1.777 AU a = 2.038 AU and e = 0.127 |
|
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|
Belt N°1 |
3.20 (4 Vesta ) |
20.9 (2003 SV100) |
2003 SV100 : q = 1.679 AU a = 3.486 AU and e = 0.349 |
|
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|
Cybele |
6.6 ( 65 Cybele ) |
19.5 ( 2002 JE109 ) |
2002 JE109 : q = 1.676 AU a = 3.322 AU and e = 0.495 |
|
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|
Hilda |
7.5 ( 153 Hilda ) |
17.9 ( 2002 UP36 ) |
2002 UP36 : q = 2.125 AU a = 3.890 AU and e = 0.453 |
|
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|
Jupiter-Trojan East |
7.49 ( 624 Hektor ) |
15.4 ( 2002 AT14 ) |
2002 AT14 : q = 3.624 AU a = 5.148 AU and e = 0.296 |
|
|
|
Jupiter-Trojan West |
8.1 ( 3451 Mentor ) |
15.1 ( 2000 QV233 ) |
2000 QV233 : q = 3.859 AU a = 5.132 AU and e = 0.248 |
|
|
|
Centaur |
6.0 ( 1995 SN55 ) |
14.3 ( 2000 GM37 ) |
2000 GM137 : q = 6.927 AU a = 7.883 AU and e = 0.121 |
|
|
|
Inner KBO |
4.5 ( 2002 KX14 ) |
9.3 ( 1996 AS20 ) |
1996 AS20 : q = 13.565 AU a = 35.787 AU and e = 0.621 |
|
|
|
Plutino |
- 1.1 ( Pluto ) |
12.4 ( 1999 DA8 ) |
1997 DA8 : q = 26.401 AU a = 39.316 AU and e = 0.329 |
|
|
|
Cubewano |
2.6 ( 50000 Quaoar ) |
11.9 ( 2003 BH91 ) |
low e |
|
|
|
SDO |
3,9 ( 2000 TC302 ) |
14.1 ( 2003 QM12 ) |
2003 QM112 : q = 13.169 AU a = 83.397 AU et e = 0.842 |
|
|
|
Oort ? |
9.1 (2000 OO67 ) |
14.0 ( 1996 PW ) |
very high e |
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Remarks: |
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* Definitive records are shown in "bold". |
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* The minimum H magnitude reached for each group is often for objects having high eccentricities or by those close to the inner edge of the zone. |
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The H magnitude limit reached by asteroids of intermediate or low eccentricity are relatively less bright. |
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* The largest asteroids not definitively associated with the Belt N°1 ( inner, central or outer zone ) and found up until 2003 (given that there has not been |
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a large error in the H magnitude, something which is currently still fairly frequent ) are of the following H magnitudes : |
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Period 1951 to 2001 |
Period 2001 to 2003 |
|
|
|
Inner Zone |
13.3 |
13.6 |
|
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|
Central Zone |
12.4 |
13.1 |
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Outer Zone |
12.1 |
12.8 |
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The largest asteroids having H mag < 5.0 listed in order of H magnitude ( as of 20-May-04 ) : |
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|
NAME |
PROVISIONAL NAME |
MAGNITUDE H |
DIAM. actual or (estimated) in km |
GROUP |
ALBEDO |
|
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|
|
|
|
|
|
|
|
Pluto |
- |
- 1.1 |
2262 to 2320 |
Plutino |
60% |
|
|
|
(Charon) |
- |
+ 0.9 |
1270 |
Plutino |
40% |
|
|
|
Sedna ? |
2003 VB12 |
+ 1.6 |
1600 ? |
ESDO ? |
>13% |
|
|
|
- |
2004 DW |
+ 2.4 |
|
Plutino |
|
|
|
|
50000 Quaoar |
2002 LM60 |
+ 2.6 |
1250 +/-50 (Brown / Trujillo - HST) |
Cubewano |
12% |
|
|
|
4 Vesta |
- |
+ 3.20 |
530 |
Belt N°1 |
38% |
|
|
|
28978 Ixion |
2001 KX76 |
+ 3.2 |
1055 +/-165 ( Bertoldi et al. - IRAM ) |
Plutino |
9% |
|
|
|
55565 2002 AW197 |
2002 AW197 |
+ 3.3 |
890 +/-120 ( Margot et al - IRAM ) |
SDO |
10% |
|
|
|
55636 2002 TX300 |
2002 TX300 |
+ 3.3 |
|
Cubewano |
|
|
|
|
1 Ceres |
- |
+ 3.34 |
950 +/- 8 ( Stern et al. - HST ) |
Belt N°1 |
10% |
|
|
|
55637 2002 UX25 |
2002 UX25 |
+ 3.6 |
|
Cubewano |
|
|
|
|
20000 Varuna |
2000 WR106 |
+ 3.7 |
900 +/-140 ( D.Jewitt - JCMT ) |
Cubewano |
7% |
|
|
|
- |
2002 MS4 |
+ 3.9 |
|
Cubewano |
|
|
|
|
(84522) 2002 TC302 |
2002 TC302 |
+ 3.9 |
|
SDO |
|
|
|
|
- |
2004 GV9 |
+ 3.9 |
|
Cubewano |
|
|
|
|
- |
2003 AZ84 |
+ 4.0 |
|
Plutino |
|
|
|
|
2 Pallas |
- |
+ 4.13 |
498 |
Belt N°1 |
14% |
|
|
|
42301 2001 UR163 |
2001 UR163 |
+ 4.2 |
|
SDO |
|
|
|
- |
2003 QM91 |
+ 4.2 |
|
Cubewano |
|
|
|
(84922) 2003 VS2 |
2003 VS2 |
+ 4.2 |
|
Plutino |
|
|
|
|
19308 1996 TO66 |
1996 TO66 |
+ 4.5 |
(709) (in 2000 by Gil-Hutton) |
Cubewano |
|
|
|
- |
2002 KX14 |
+ 4.5 |
|
Inner KBO II |
|
|
|
- |
2003 QW90 |
+ 4.5 |
|
Cubewano |
|
|
|
26375 1999 DE9 |
1999 DE9 |
+ 4.7 |
|
SDO 5:2 |
|
|
|
38628 Huya |
2000 EB173 |
+ 4.7 |
(696 with H=+5.09) (Barucci et al) |
Plutino |
4% |
|
|
|
- |
2001 QF298 |
+ 4.7 |
|
Plutino |
|
|
|
- |
2002 WC19 |
+ 4.7 |
|
KBO 2:1 |
|
|
|
24835 1995 SM55 |
1995 SM55 |
+ 4.8 |
(813) (in 2000 by Gil-Hutton) |
Cubewano |
|
|
|
- |
2003 FY128 |
+ 4.8 |
|
SDO |
|
|
|
|
19521 Chaos |
1998 WH24 |
+ 4.9 |
|
Cubewano |
|
|
|
47171 1999 TC36 |
1999 TC36 |
+ 4.9 |
675 +/-100 ( Bertholdi et al - IRAM ) |
Plutino |
3.5% |
|
|
|
- |
2002 CY248 |
+ 4.9 |
|
Cubewano |
|
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NB: Main-belt asteroids ( Mars to Jupiter) in red and asteroids from Belt N°2 (TNOs) in black |
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There are 3 large asteroids in the Belt N°1 compared with 26 for Belt N°2. The Principal Belt is no longer that which one used to believe… |
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The smallest asteroids ( as of 25-May-04 ) : |
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Numbered asteroids |
= Mag H 22.7 for |
(54509) 2000 PH5 (Ap.1) |
(65717) 1993 BX3 (H = 21.0 /Am.3 ) |
(41429) 2000 GE2 ( 20.7 /Ap.2) |
|
|
Unnumbered asteroids |
= Mag H 30.1 for |
2003 SQ222 (Apollo 1) |
2003 YS70 (H=29.2 /Ap.1) |
2003 SW130 (H= 29.1 /Aten) |
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On 26 October 1995, the Spacewatch Telescope observed an asteroid named "SS-291" of 2 to 4 meters in diameter ( H = 31.0 ) (source MPML 25-Oct-02) |
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An unconfirmed suspect estimated to be of mag H 30.6 and named "P00ACE", was observed by LONEOS on the 28th and 29th September 2003 of the |
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Apollo 1 type ( a = 1.408 AU and e = 0.474 ), it would have been between 2-5 meters across. It passed as close as 89,800 km to Earth on 27.94 September 2003 |
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( MPML 30-Sep-03 ). |
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Magnitude H = 18.2 corresponds to more or less 1 km in diameter: |
Estimated number 1 km or more in size = > 5,000,000 !.. numbered = |
73 636 |
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Shortest rotational periods of the asteroids ( < 10 minutes ) known as of 05-Dec-03 |
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2000 DO8 |
APOLLO 3 |
85x40 m across |
Rotation period = 1.3038 min |
|
H = 24.8 |
|
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|
2000 WH10 |
APOLLO 3 |
130 m diameter |
Rotation period = 1.374 min |
|
H = 22.5 |
|
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|
2003 EM1 |
ATEN |
55 m diameter |
Rotation period = 1.858 min |
|
H = 24.5 |
(CDR+CDL website) |
|
2003 DW10 |
APOLLO 1 |
25 m diameter |
Rotation period < 2 min |
|
H = 26.1 |
(MPML 08-Mar-03) |
|
2003 EP4 |
APOLLO 1 |
70 m diameter |
Rotation period ~ 2 min |
|
H = 23.9 |
(MPML 13-Mar-03) |
|
1999 SF10 |
APOLLO 1 |
60 m diameter |
Rotation period = 2.466 min |
|
H = 24.2 |
|
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|
2001 WV1 |
APOLLO 1 |
130 m diameter |
Rotation period = 2.694 min |
|
H = 22.5 |
|
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2000 UK11 |
ATEN |
40 m diameter |
Rotation period = 3 min |
|
H = 25.3 |
|
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|
2004 FH |
ATEN |
30 m diameter |
Rotation period = 3.023 min |
|
H = 25.7 |
|
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|
2001 SQ3 |
APOLLO 1 |
200 m diameter |
Rotation period = 3.75 min |
|
H = 21.7 |
|
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|
2000 WS28 |
APOLLO 2 |
75 m diameter |
Rotation period = 4.386 min |
|
H = 23.6 |
|
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|
2000 AG6 |
APOLLO 1 |
80x35 m across |
Rotation period = 4.598 min |
|
H = 25.3 |
|
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1999 TY2 |
APOLLO 3 |
80 m diameter |
Rotation period = 7.280 min |
|
H = 23.3 |
|
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2000 WG63 |
AMOR 2 |
100 m diameter |
Rotation period = 8.238 min |
|
H = 23.2 |
|
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2000 WL107 |
AMOR 3 |
50 m diameter |
Rotation period = 9.654 min |
|
H = 24.8 |
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2000 WQ148 |
APOLLO 2 |
125 m diameter |
Rotation period = 9.9 min |
|
H = 22.7 |
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They comprise only small asteroids, fragments from collisions between larger asteroids. |
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These objects must obligatorily be monolithic, in contrast to larger asteroids which must be 'rubble piles', which cannot withstand such a rapid rotation. |
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Only one fast-rotator is currently numbered : |
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(54509) 2000 PH5 |
APOLLO 1 |
125 m diameter |
Rotation period = 12.172 min |
|
H = 22.7 |
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For larger (estimated) diameters of asteroids, we have the following records : |
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2000 WL10 |
APOLLO 3 |
1080 m diameter |
Rotation period = 19.308 min |
|
H = 18.0 |
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2001 OE84 |
AMOR 3 |
900 m diameter |
Rotation period = 29.2 min |
|
H = 17.8 |
|
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|
1335 Demoulina |
Belt N°1 |
~ 11 km diameter |
Rotation period ~ 14.4 min ? ( uncertain ) |
H = 12.9 |
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The 13 asteroids currently having the longest rotation period known as of 05-Dec-03 |
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288 Glauke |
Belt N°1 |
1200 hr |
|
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|
1220 Crocus |
Belt N°1 ( Eos ) |
737 hr |
|
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|
|
253 Mathilde |
Belt N°1 |
417.7 hr |
|
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1998 QR52 |
Apollo 1 |
235 hr |
|
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|
3691 Bede |
Amor 2 |
226.8 hr |
|
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9969 Braille |
Mars-crosser |
226.4 hr |
|
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|
38071 1999 GU3 |
Amor 2 |
216 hr |
|
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|
|
65407 2002 RP120 |
Damocloid |
199.2 hr |
|
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|
|
16064 1999 RH27 |
Amor 3 |
178.6 hr |
|
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|
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1481 Tubingia |
Belt N°1 |
160 hr |
|
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|
|
2003 KP2 |
Apollo 3 |
150.7 hr |
|
|
|
|
3102 Krok |
Amor 3 |
147.8 hr |
|
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1689 Floris-Jan |
Belt N°1 ( Eurynome ) |
145 hr |
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While the majority of asteroids have a single rotational axis, some small planets having a very slow rotation rate do not revolve about one axis. |
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Following collisions in the past, they tumble themselves, and because of this fact they are prevented from displaying a similar aspect in successive lightcurves. |
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They have at least two different rotation periods. |
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They are referred to as "Tumbling Asteroids". The largest of them is 253 Mathilde ( diameter 53 km and principal rotation period of 17.41 days ) |
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The most studied of the small "tumbling asteroids" is the Earth-crosser 4179 Toutatis for which the rotational axis undergoes a precessional motion giving |
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two rotation periods of 7.42 and 5.37 days. |
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Other known examples are : 1689 Floris-Jan, 3288 Seleucus, 3691 Bede, 1997 BR and 38071 1999 GU3 and of course 288 Glauke (diameter 32 km). |
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Distribution of the 1724 asteroid rotation periods as compiled by G.Faure as of 05-Dec-03 |
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Period of rotation |
Number of asteroids |
% of total |
Cumulative no. with period < x hr |
|
Cumulative % |
|
|
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|
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|
Less than 1 hr |
33 |
2.0% |
33 |
|
2.0% |
|
|
|
1 to < 2 hr |
8 |
0.5% |
41 |
|
2.5% |
|
|
|
2 to < 3 hr |
92 |
5.7% |
133 |
|
8.2% |
|
|
|
3 to < 4 hr |
98 |
6.1% |
231 |
|
14.2% |
|
|
|
4 to < 5 hr |
129 |
8.0% |
360 |
|
22.3% |
|
|
|
5 to < 6 hr |
142 |
8.8% |
502 |
|
31.0% |
|
|
|
6 to < 7 hr |
141 |
8.7% |
643 |
|
39.8% |
|
|
|
7 to < 8 hr |
123 |
7.6% |
766 |
|
47.4% |
|
|
|
8 to < 9 hr |
117 |
7.2% |
883 |
|
54.6% |
|
|
|
9 to < 10 hr |
91 |
5.6% |
974 |
|
60.2% |
|
|
|
10 to < 11 hr |
76 |
4.7% |
1050 |
|
64.9% |
|
|
|
11 to < 12 hr |
56 |
3.5% |
1106 |
|
68.4% |
|
|
|
12 to < 13 hr |
56 |
3.5% |
1162 |
|
71.9% |
|
|
|
13 to < 14 hr |
42 |
2.6% |
1204 |
|
74.5% |
|
|
|
14 to < 15 hr |
43 |
2.7% |
1247 |
|
77.1% |
|
|
|
15 to < 16 hr |
48 |
3.0% |
1295 |
|
80.1% |
|
|
16 to < 17 hr |
35 |
2.2% |
1330 |
|
82.3% |
|
|
17 to < 18 hr |
26 |
1.6% |
1356 |
|
83.9% |
|
|
18 to < 19 hr |
26 |
1.6% |
1382 |
|
85.5% |
|
|
19 to < 20 hr |
27 |
1.7% |
1409 |
|
87.1% |
|
|
20 to < 21 hr |
10 |
0.6% |
1419 |
|
87.8% |
|
|
21 to < 22 hr |
8 |
0.5% |
1427 |
|
88.2% |
|
|
22 to < 23 hr |
7 |
0.4% |
1434 |
|
88.7% |
|
|
23 to < 24 hr |
11 |
0.7% |
1445 |
|
89.4% |
|
|
More than 24 hr |
172 |
10.6 |
1617 |
|
100.0% |
|
|
Total |
1617 |
100% |
|
|
|
|
|
Very uncertain periods |
107 |
|
|
|
|
|
|
Overall Total |
1724 |
The 1617 known periods represent 2.2% of the 73636 numbered asteroids + 172 unnumbered others |
|
|
|
|
|
|
|
|
NB: Where a range of possible periods exist for a given asteroid, the minimum period has been adopted, except where a more recent second period is |
|
|
|
known and more certain. The ill-defined periods are those of less than 24 hours and only quoted to the nearest hour. |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Asteroids having the greatest lightcurve variability ( > 1.40 mag ) as of 05-Dec-03 : |
|
|
|
|
|
|
|
|
|
|
1865 Cerberus |
Apollo 1 |
Max. 2.10 mag |
|
|
|
|
1620 Geographos |
Apollo 1 |
Max. 2.03 mag |
|
|
|
|
2002 TD60 |
Amor 1 |
Max. 2.0 mag |
|
|
|
|
1995 HM |
Amor 1 |
Max. 2 mag |
|
|
|
|
3485 Barucci |
Hertha (Belt N°1) |
Max. 1.78 mag ? |
( Amplitude of only 0.19 mag assessed in 2002 => ??? ) |
|
|
|
2000 EB14 |
Aten |
Max. 1.70 mag |
|
|
|
|
3102 Krok |
Amor 3 |
Max. 1.6 mag |
|
|
|
|
38071 1999 GU3 |
Amor 2 |
Max. 1.5 mag |
|
|
|
|
2002 HK12 |
Apollo 2 |
Max. 1.50 mag |
|
|
|
|
433 Eros |
Amor 1 |
Max. 1.49 mag |
|
|
|
|
1742 Schaifers |
Koronis (Belt N°1) |
Max. 1.46 mag |
|
|
|
|
|
|
|
|
|
|
NB: The Jupiter-Trojans of more than 90 km diameter appear to have a lightcurve amplitude which is on average more than that of main-belt objects |
|
|
|
( 0.198 et 0.155 magnitude respectively) |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Distribution of the 1621 maximum lightcurve amplitudes as compiled by G.Faure as of 05-Dec-03 : |
|
|
|
|
|
|
|
|
|
|
Amplitude in mag |
No. of asteroids |
% of total |
Cumulative no. with ampl < x mag |
|
Cumulative % |
|
|
|
|
|
|
|
|
|
|
|
Less than 0.1 |
122 |
7.6% |
122 |
|
8% |
|
|
|
0.1 to < 0.2 |
384 |
24.0% |
506 |
|
32% |
|
|
|
0.2 to < 0.3 |
346 |
21.6% |
852 |
|
53% |
|
|
|
0.3 to < 0.4 |
252 |
15.7% |
1104 |
|
69% |
|
|
|
0.4 to < 0.5 |
167 |
10.4% |
1271 |
|
79% |
|
|
|
0.5 to < 0.6 |
105 |
6.6% |
1376 |
|
86% |
|
|
|
0.6 to < 0.7 |
65 |
4.1% |
1441 |
|
90% |
|
|
|
0.7 to < 0.8 |
41 |
2.6% |
1482 |
|
92% |
|
|
|
0.8 to < 0.9 |
35 |
2.2% |
1517 |
|
95% |
|
|
|
0.9 to < 1.0 |
26 |
1.6% |
1543 |
|
96% |
|
|
|
1.0 to < 1.1 |
15 |
0.9% |
1558 |
|
97% |
|
|
|
1.1 to < 1.2 |
15 |
0.9% |
1573 |
|
98% |
|
|
|
1.2 to < 1.3 |
10 |
0.6% |
1583 |
|
99% |
|
|
|
1.3 to < 1.4 |
5 |
0.3% |
1588 |
|
99% |
|
|
|
1.4 to < 1.5 |
7 |
0.4% |
1595 |
|
100% |
|
|
|
1.5 to < 1.6 |
2 |
0.1% |
1597 |
|
100% |
|
|
|
1.6 to < 1.7 |
1 |
0.1% |
1598 |
|
100% |
|
|
|
1.7 to < 1.8 |
1 |
0.1% |
1599 |
|
100% |
|
|
|
1.8 to < 1.9 |
0 |
0.0% |
1599 |
|
100% |
|
|
|
1.9 to < 2.0 |
0 |
0.0% |
1599 |
|
100% |
|
|
|
2.0 and more |
4 |
0.2% |
1603 |
|
100% |
|
|
|
Total |
1603 |
100% |
|
|
|
|
|
|
Uncertain amplitudes |
107 |
|
|
|
|
|
|
|
Overall Total |
1710 |
The 1710 known periods represent 2.1% of the 73636 numbered asteroids + 172 unnumbered others |
|
|
|
|
|
|
|
|
|
|
|
NB: Where a range of possible amplitudes exist for a given asteroid, the maximum one has been adopted |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Generally, it is the larger asteroids that have been studied at first, since these have been more accessible to the amateurs or to the Astronomers equipped with photometers. |
|
It has been shown that high-amplitude lightcurves are not very numerous, at least amongst the larger asteroids. |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
In the context of refining or verifying to a tenth of a magnitude the H magnitudes of the minor planets, that which is interesting and should be noted : |
|
|
|
|
|
|
|
|
|
|
|
|
- the expected variation is only the half-amplitude (thus at most 0.2 mag for 75% of asteroids !) either side of the H magnitude that can alter the measures in general. |
|
|
- The table above summarises the maximum amplitude for each asteroid. Each object amongst them can of cause exhit a lower amplitude. |
|
|
|
|
- Finally, the elapsed time between maximum and minimum light for an asteroid is only a small part of the rotation period, so this change does not reoccur that frequently. |
|
|
|
|
|
|
|
|
|
|
It follows that the intrinsic variability is often less problematic in practice, if the aim is to achieve a precision of 0.1 mag as required particularly by the MAP ( Magnitude |
|
Alert Project ). A good number of measurements over several oppositions and a statistical average most often results in levelling out any deviation owing to variability. |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Distribution of the 206295 Asteroids by magnitude H as of 31-Dec-03 : |
|
|
|
|
|
NB: The albedo ( % sunlight reflected ) of each asteroid varies depending on the type of surface, therefore the dimensions quoted comprise ranges of size |
|
|
|
|
|
|
|
ABSOLUTE MAG |
DIAMETER in KM |
TOTAL NUMBERED |
TOTAL UNNUMBERED |
|
OVERALL TOTAL |
% TOTAL |
|
Magnitude H = -1 |
2280 |
0 |
1 |
|
1 |
|
0.0 |
|
Magnitude H = 1 |
1600 |
0 |
0 |
|
0 |
|
0.0 |
|
Magnitude H = 2 |
1250 |
1 |
0 |
|
1 |
|
0.0 |
|
Magnitude H = 3 |
420 to 1500 |
8 |
2 |
|
10 |
|
0.0 |
|
Magnitude H = 4 |
260 to 940 |
8 |
9 |
|
17 |
|
0.0 |
|
Magnitude H = 5 |
170 to 590 |
17 |
59 |
|
76 |
|
0.0 |
|
Magnitude H = 6 |
110 to 370 |
43 |
225 |
|
268 |
|
0.1 |
|
Magnitude H = 7 |
65 to 240 |
123 |
284 |
|
407 |
|
0.2 |
|
Magnitude H = 8 |
40 to 150 |
231 |
155 |
|
386 |
|
0.2 |
|
Magnitude H = 9 |
25 to 95 |
456 |
52 |
|
508 |
|
0.2 |
|
Magnitude H = 10 |
17 to 60 |
722 |
24 |
|
746 |
|
0.4 |
|
Magnitude H = 11 |
11 to 37 |
1923 |
57 |
|
1980 |
|
1.0 |
|
Magnitude H = 12 |
7 to 24 |
5262 |
406 |
|
5668 |
|
2.7 |
|
Magnitude H = 13 |
4 to 15 |
14603 |
2821 |
|
17424 |
|
8.4 |
|
Magnitude H = 14 |
3 to 9 |
24077 |
18903 |
|
42980 |
|
20.8 |
|
Magnitude H = 15 |
2 to 6 |
19560 |
42496 |
|
62056 |
|
30.1 |
|
Magnitude H = 16 |
1 to 4 |
6013 |
44225 |
|
50238 |
|
24.4 |
|
Magnitude H = 17 |
0.7 to 2 |
506 |
17705 |
|
18211 |
|
8.8 |
|
Magnitude H = 18 |
0.4 to 1.5 |
48 |
3265 |
|
3313 |
|
1.6 |
|
Magnitude H = 19 |
0.3 to 0.9 |
28 |
790 |
|
818 |
|
0.4 |
|
Magnitude H = 20 |
0.2 to 0.6 |
5 |
432 |
|
437 |
|
0.2 |
|
Magnitude H = 21 |
0.1 to 0.4 |
1 |
233 |
|
234 |
|
0.1 |
|
Magnitude H = 22 |
0.07 to 0.24 |
1 |
163 |
|
164 |
|
0.1 |
|
Magnitude H = 23 |
0.04 to 0.15 |
0 |
111 |
|
111 |
|
0.1 |
|
Magnitude H = 24 |
0.025 to 0.095 |
0 |
109 |
|
109 |
|
0.1 |
|
Magnitude H = 25 |
0.017 to 0.060 |
0 |
58 |
|
58 |
|
0.0 |
|
Magnitude H = 26 |
0.011 to 0.037 |
0 |
40 |
|
40 |
|
0.0 |
|
Magnitude H = 27 |
0.007 to 0.024 |
0 |
15 |
|
15 |
|
0.0 |
|
Magnitude H = 28 |
0.004 to 0.015 |
0 |
6 |
|
6 |
|
0.0 |
|
Magnitude H = 29 |
0.003 to 0.009 |
0 |
4 |
|
4 |
|
0.0 |
|
Magnitude H = 30 |
0.002 to 0.006 |
0 |
1 |
|
1 |
|
0.0 |
|
Number of asteroids concerned |
73636 |
132651 |
|
206287 |
|
100.0 |
|
|
|
|
Asteroids with unknown mag H |
8 |
|
|
|
|
|
|
206295 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Number of asteroids per magnitude H for all-known asteroids ( numbered and unnumbered ) as of 31-Dec-03 : |
|
|
|
|
|
|
|
|
|
Absolute |
a < 4.9 AU |
4.9 AU < a < 5.5 AU |
5.5 AU < a < 30.6 AU |
a > 30.59 AU |
Overall Total |
|
magnitudes |
( Inner asteroids ) |
( Jupiter-zone asteroids ) |
( Centaurs ) |
( TNO +Oort ) |
|
|
|
|
|
|
|
|
|
|
Mag H -1 |
|
|
1 |
1 |
|
Mag H -0 |
|
|
|
0 |
|
Mag H +0 |
|
|
|
0 |
|
Mag H +1 |
|
|
|
0 |
|
Mag H +2 |
|
|
1 |
1 |
|
Mag H +3 |
2 |
|
7 |
9 |
|
Mag H +4 |
1 |
|
16 |
17 |
|
Mag H +5 |
10 |
|
67 |
77 |
|
Mag H +6 |
24 |
|
4 |
240 |
268 |
|
Mag H +7 |
96 |
3 |
4 |
304 |
407 |
|
Mag H +8 |
200 |
22 |
9 |
155 |
386 |
|
Mag H +9 |
374 |
77 |
12 |
45 |
508 |
|
Mag H +10 |
584 |
137 |
11 |
14 |
746 |
|
Mag H +11 |
1568 |
400 |
7 |
5 |
1980 |
|
Mag H +12 |
5147 |
511 |
8 |
2 |
5668 |
|
Mag H +13 |
17024 |
390 |
10 |
|
17424 |
|
Mag H +14 |
42873 |
100 |
4 |
3 |
42980 |
|
Mag H +15 |
62049 |
3 |
3 |
1 |
62056 |
|
Mag H +16 |
50235 |
0 |
3 |
|
50238 |
|
Mag H +17 |
18208 |
2 |
1 |
|
18211 |
|
Mag H +18 |
3313 |
0 |
0 |
|
3313 |
|
Mag H +19 |
818 |
0 |
0 |
|
818 |
|
Mag H +20 |
437 |
0 |
0 |
|
437 |
|
Mag H +21 |
234 |
0 |
0 |
|
234 |
|
Mag H +22 |
164 |
0 |
0 |
|
164 |
|
Mag H +23 |
111 |
0 |
0 |
|
111 |
|
Mag H +24 |
109 |
0 |
0 |
|
109 |
|
Mag H +25 |
58 |
0 |
0 |
|
58 |
|
Mag H +26 |
40 |
0 |
0 |
|
40 |
|
Mag H +27 |
15 |
0 |
0 |
|
15 |
|
Mag H +28 |
6 |
0 |
0 |
|
6 |
|
Mag H +29 |
4 |
0 |
0 |
|
4 |
|
Mag H +30 |
1 |
0 |
0 |
|
1 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Totaux |
203705 |
1645 |
76 |
861 |
206287 |
|
|
|
|
Asteroids with unknown mag H |
|
8 |
|
|
|
|
|
Overall Total |
206295 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Distribution of numbered asteroids by magnitude H for the first 85117 asteroids |
|
|
|
|
|
|
|
|
|
|
Absolute |
a < 4.9 AU |
4.9 AU < a < 5.5 AU |
5.5 AU < a < 30.6 AU |
a > 30.59 AU |
Overall Total |
|
magnitudes |
( Inner asteroids ) |
( Jupiter-zone asteroids ) |
( Centaurs ) |
( TNO +Oort ) |
|
|
|
|
|
|
|
|
|
|
Mag H +2 |
|
|
1 |
1 |
|
Mag H +3 |
2 |
|
6 |
8 |
|
Mag H +4 |
1 |
|
8 |
9 |
|
Mag H +5 |
10 |
|
13 |
23 |
|
Mag H +6 |
24 |
|
2 |
22 |
48 |
|
Mag H +7 |
96 |
3 |
3 |
23 |
125 |
|
Mag H +8 |
200 |
22 |
1 |
8 |
231 |
|
Mag H +9 |
374 |
77 |
6 |
|
457 |
|
Mag H +10 |
584 |
137 |
3 |
|
724 |
|
Mag H +11 |
1568 |
364 |
2 |
|
1934 |
|
Mag H +12 |
5093 |
223 |
1 |
1 |
5318 |
|
Mag H +13 |
15281 |
52 |
3 |
|
15336 |
|
Mag H +14 |
27549 |
|
|
27549 |
|
Mag H +15 |
24182 |
|
|
24182 |
|
Mag H +16 |
8409 |
|
|
8409 |
|
Mag H +17 |
680 |
|
|
680 |
|
Mag H +18 |
48 |
|
|
48 |
|
Mag H +19 |
28 |
|
|
28 |
|
Mag H +20 |
5 |
|
|
5 |
|
Mag H +21 |
1 |
|
|
1 |
|
Mag H +22 |
1 |
|
|
1 |
|
TOTALS |
84136 |
878 |
21 |
82 |
85117 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Average magnitude H per thousand asteroids for the first 73000 numbered objects |
|
|
|
|
|
|
|
|
|
|
1 to 999 |
9.6 |
37000 to 37999 |
14.8 |
|
|
|
1000 to 1999 |
11.6 |
38000 to 38999 |
14.7 |
|
|
|
2000 to 2999 |
12.4 |
30000 to 39999 |
14.9 |
|
|
|
3000 to 3999 |
12.7 |
40000 to 40999 |
14.8 |
|
|
|
4000 to 4999 |
12.8 |
41000 to 41999 |
14.7 |
|
|
|
5000 to 5999 |
12.9 |
42000 to 42999 |
14.7 |
|
|
|
6000 to 6999 |
13.2 |
43000 to 43999 |
14.7 |
|
|
|
7000 to 7999 |
13.5 |
44000 to 44999 |
14.9 |
|
|
|
8000 to 8999 |
13.7 |
45000 to 45999 |
14.5 |
|
|
|
9000 to 9999 |
13.9 |
46000 to 46999 |
14.8 |
|
|
|
10000 to 10999 |
13.9 |
47000 to 47999 |
14.6 |
|
|
|
11000 to 11999 |
13.9 |
48000 to 48999 |
14.9 |
|
|
|
12000 to 12999 |
14,0 |
40000 to 49999 |
14.8 |
|
|
|
13000 to 13999 |
13.8 |
50000 to 50999 |
14.7 |
|
|
|
14000 to 14999 |
13.9 |
51000 to 51999 |
14.4 |
|
|
|
15000 to 15999 |
13.8 |
52000 to 52999 |
15.1 |
|
|
|
16000 to 16999 |
14.1 |
53000 to 53999 |
15,0 |
|
|
|
17000 to 17999 |
14.1 |
54000 to 54999 |
14.8 |
|
|
|
18000 to 18999 |
14.3 |
55000 to 55999 |
14.8 |
|
|
|
19000 to 19999 |
14.3 |
56000 to 56999 |
15,0 |
|
|
|
20000 to 20999 |
14.3 |
57000 to 57999 |
15,0 |
|
|
|
21000 to 21999 |
14.5 |
58000 to 58999 |
15,0 |
|
|
|
22000 to 22999 |
14.5 |
59000 to 59999 |
15.3 |
|
|
|
23000 to 23999 |
14.4 |
60000 to 60999 |
15.5 |
|
|
|
24000 to 24999 |
14.4 |
61000 to 61999 |
15.5 |
|
|
|
25000 to 25999 |
14.4 |
62000 to 62999 |
15.2 |
|
|
|
26000 to 26999 |
14.5 |
63000 to 63999 |
15.3 |
|
|
|
27000 to 27999 |
14.3 |
64000 to 64999 |
15.6 |
|
|
|
28000 to 28999 |
14.3 |
65000 to 65999 |
15.5 |
|
|
|
29000 to 29999 |
14.2 |
66000 to 66999 |
15.2 |
|
|
|
30000 to 30999 |
14.4 |
67000 to 67999 |
15.4 |
|
|
|
31000 to 31999 |
14.3 |
68000 to 68999 |
15.4 |
|
|
|
32000 to 32999 |
14.3 |
69000 to 69999 |
15.3 |
|
|
|
33000 to 33999 |
14.6 |
70000 to 70999 |
15.4 |
|
|
|
34000 to 34999 |
14.5 |
71000 to 71999 |
14.9 |
|
|
|
|
35000 to 35999 |
14.8 |
72000 to 73000 |
15.2 |
|
|
|
36000 to 36999 |
14.7 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Distribution of numbered asteroids by brightest V magnitude during the period 2003-2050 (first 73000 asteroids) |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
V Magnitude |
a < 4.9 AU |
4.9 AU < a < 5.5 AU |
5.5 AU < a < 30.6 AU |
a > 30.59 AU |
Overall total |
|
|
( Inner asteroids ) |
( Jupiter-zone asteroids ) |
( Centaurs ) |
( TNO +Oort ) |
|
|
|
Max. mag V + 5 |
1 |
|
|
|
1 |
|
Max. mag V + 6 |
3 |
|
|
|
3 |
|
Max. mag V + 7 |
5 |
|
|
|
5 |
|
Max. mag V + 8 |
20 |
|
|
|
20 |
|
Max. mag V + 9 |
42 |
|
|
|
42 |
|
Max. mag V + 10 |
120 |
|
|
|
120 |
|
Max. mag V + 11 |
187 |
|
|
|
187 |
|
Max. mag V + 12 |
373 |
|
|
|
373 |
|
Max. mag V + 13 |
831 |
|
1 |
|
832 |
|
Max. mag V + 14 |
2848 |
13 |
|
|
2861 |
|
Max. mag V + 15 |
9343 |
51 |
1 |
|
9395 |
|
Max. mag V + 16 |
20235 |
114 |
3 |
|
20352 |
|
Max. mag V + 17 |
24994 |
241 |
3 |
1 |
25239 |
|
Max. mag V + 18 |
11769 |
304 |
4 |
2 |
12079 |
|
Max. mag V + 19 |
1295 |
101 |
2 |
8 |
1406 |
|
Max. mag V + 20 |
13 |
10 |
2 |
7 |
32 |
|
Max. mag V + 21 |
|
13 |
13 |
|
Max. mag V + 22 |
|
3 |
17 |
20 |
|
Max. mag V + 23 |
|
1 |
16 |
17 |
|
Max. mag V + 24 |
|
3 |
3 |
|
Max. mag V + 25 |
|
|
0 |
|
TOTALS |
72079 |
834 |
20 |
67 |
73000 |
|
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|
Cumulative distribution of numbered asteroids versus limiting V magnitude for the period 2003-2050 (first 73000 asteroids) |
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The data below allows one to estimate the maximum number asteroids observable for a given magnitude limit depending on the equipment used |
|
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and local observing conditions : |
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|
|
V Mag max.observable |
Cumulative no. of asteroids |
V Mag max.observable |
Cumulative no. of asteroids |
|
|
|
5.0-5.4 |
1 |
14.0-14.4 |
2503 |
|
|
|
5.5-5.9 |
1 |
14.5-14.9 |
4444 |
|
|
|
6.0-6.4 |
1 |
15.0-15.4 |
7940 |
|
|
|
6.5-6.9 |
4 |
15.5-15.9 |
13838 |
|
|
|
7.0-7.4 |
5 |
16.0-16.4 |
22611 |
|
|
|
7.5-7.9 |
9 |
16.5-16.9 |
34190 |
|
|
|
8.0-8.4 |
17 |
17.0-17.4 |
47456 |
|
|
|
8.5-8.9 |
29 |
17.5-17.9 |
59429 |
|
|
|
9.0-9.4 |
44 |
18.0-18.9 |
71509 |
|
|
|
9.5-9.9 |
71 |
19.0-19.9 |
72915 |
|
|
|
10.0-10.4 |
118 |
20.0-20.9 |
72947 |
|
|
|
10.5-10.9 |
191 |
21.0-21.9 |
72960 |
|
|
|
11.0-11.4 |
272 |
22.0-22.9 |
72980 |
|
|
|
11.5-11.9 |
378 |
23.0-23.9 |
72997 |
|
|
|
12.0-12.4 |
530 |
24.0-24.9 |
73000 |
|
|
|
12.5-12.9 |
751 |
25.0-25.9 |
73000 |
|
|
|
13.0-13.4 |
1080 |
|
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|
|
13.5-13.9 |
1583 |
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Average maximum V magnitude per thousand asteroids for the first 73000 numbered objects |
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|
1 to 999 |
12.4 |
37000 to 37999 |
17.4 |
|
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|
1000 to 1999 |
14.2 |
38000 to 38999 |
17.3 |
|
|
|
2000 to 2999 |
14.9 |
30000 to 39999 |
17.4 |
|
|
|
3000 to 3999 |
15.1 |
40000 to 40999 |
17.4 |
|
|
|
4000 to 4999 |
15.3 |
41000 to 41999 |
17.3 |
|
|
|
5000 to 5999 |
15.3 |
42000 to 42999 |
17.3 |
|
|
|
6000 to 6999 |
15.5 |
43000 to 43999 |
17.2 |
|
|
|
7000 to 7999 |
15.8 |
44000 to 44999 |
17.2 |
|
|
|
8000 to 8999 |
16.1 |
45000 to 45999 |
17.1 |
|
|
|
9000 to 9999 |
16.2 |
46000 to 46999 |
17.3 |
|
|
|
10000 to 10999 |
16.3 |
47000 to 47999 |
17.3 |
|
|
|
11000 to 11999 |
16.4 |
48000 to 48999 |
17.2 |
|
|
|
12000 to 12999 |
16.4 |
40000 to 49999 |
17.1 |
|
|
|
13000 to 13999 |
16.4 |
50000 to 50999 |
17.3 |
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|
|
14000 to 14999 |
16.3 |
51000 to 51999 |
17.3 |
|
|
|
15000 to 15999 |
16.5 |
52000 to 52999 |
17.4 |
|
|
|
16000 to 16999 |
16.6 |
53000 to 53999 |
17.3 |
|
|
|
17000 to 17999 |
16.8 |
54000 to 54999 |
17.5 |
|
|
|
18000 to 18999 |
16.8 |
55000 to 55999 |
17.6 |
|
|
|
19000 to 19999 |
16.9 |
56000 to 56999 |
17.4 |
|
|
|
20000 to 20999 |
16.9 |
57000 to 57999 |
17.6 |
|
|
|
21000 to 21999 |
17.0 |
58000 to 58999 |
17.9 |
|
|
|
22000 to 22999 |
17.0 |
59000 to 59999 |
17.8 |
|
|
|
23000 to 23999 |
17.0 |
60000 to 60999 |
18.1 |
|
|
|
24000 to 24999 |
17.0 |
61000 to 61999 |
17.8 |
|
|
|
25000 to 25999 |
17.0 |
62000 to 62999 |
18.1 |
|
|
|
26000 to 26999 |
16.9 |
63000 to 63999 |
18.0 |
|
|
|
27000 to 27999 |
16.8 |
64000 to 64999 |
18.1 |
|
|
|
28000 to 28999 |
16.8 |
65000 to 65999 |
17.7 |
|
|
|
29000 to 29999 |
16.8 |
66000 to 66999 |
17.6 |
|
|
|
30000 to 30999 |
16.9 |
67000 to 67999 |
17.6 |
|
|
|
31000 to 31999 |
16.9 |
68000 to 68999 |
17.9 |
|
|
|
32000 to 32999 |
17.0 |
69000 to 69999 |
17.9 |
|
|
|
33000 to 33999 |
17.0 |
70000 to 70999 |
17.7 |
|
|
|
34000 to 34999 |
17.3 |
71000 to 71999 |
17.7 |
|
|
|
35000 to 35999 |
17.2 |
72000 to 73000 |
17.9 |
|
|
|
36000 to 36999 |
17.3 |
|
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|
Satellites of Asteroids observed as of 20-May-04 |
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ASTEROID |
SATELLITE NAME |
DIAM.in km (#delta mag) |
DISCOVERY (Reference) |
"a"in km |
"P" |
GROUP |
|
|
|
|
|
Pluto |
Charon |
1230 km |
1977 - Christy (MPML 01-Apr-01) |
19636 |
6.4 days |
Plutino |
|
|
22 Kalliope |
Linus |
ratio 1/5 (# 4.9 mag) |
2001 - Merline + Margot (IAUC 7703) |
1000 |
? |
|
|
|
45 Eugenia |
Petit-Prince |
13 km (# 6.14 mag) |
1998 - Merline (MPML 01-Apr-01) |
1190 |
4.7 days |
|
|
|
87 Sylvia |
S/ 2001 (87) 1 |
< 10 km (# 6.5 mag) |
2001 - Brown et al.# (MPML 01-Mar-01) |
1200 |
4 days |
|
|
|
90 Antiope |
S/ 2000 (90) 1 |
( # < 0.1 mag) |
2000 - Merline et al. (IAUC 7503) |
170 |
16 hr |
Themis |
|
|
107 Camilla |
S/ 2001 (107) 1 |
8 km ? (# 7.0 mag) |
2001 - Storrs (IAUC 7599) |
0.6 arcsec |
? |
Cybele |
|
|
121 Hermione |
S/ 2002 (121) 1 |
13 km / Hermione = 230 km |
2002 - Merline (IAUC 7980) |
790 |
? |
|
|
|
130 Elektra |
S/ 2003 (130) 1 |
4 km (# 8.5 mag K) |
2003 - Merline (IAUC 8183) |
1170 |
? |
|
|
|
243 Ida |
Dactyl |
1.2x1.4x1.6 km (# 6.0 mag) |
1993 - Galileo probe (MPML 01-Apr-01) |
85 |
? |
|
|
|
283 Emma |
S/ 2003 (283) 1 |
12 km (# 5.5 mag) |
2003 - Merline (IAUC 8165) |
370 |
? |
|
|
|
379 Huenna |
S/ 2003 (379) 1 |
ratio 1/13 |
2003 - Margot et al. (IAUC 8182) |
1200 |
? |
|
|
|
617 Patroclus |
S/2001 (617) 1 |
same size (# 0.2 mag) |
2001 - Merline et al. (IAUC 7741) |
0.21 arcsec |
? |
J-Trojan |
|
|
762 Pulcova |
S/ 2000 (762) 1 |
9 km (# 4 mag) |
2000 - Merline (MPML 01/04/01) |
800 |
4 days |
|
|
|
1509 Esclangona |
S/2003 (1509) 1 |
4 km (# 2.4 mag K) |
2003 - Merline et al. (IAUC 8075) |
140 |
? |
Hungaria |
|
|
3749 Balam |
S/2002 (3749) 1 |
7 and 1.5 km (# 0.2 mag) |
2002 - Merline et al. (IAUC 7827) |
? |
80 days |
|
|
|
3782 Celle |
S/2003 (5381) 1 |
ratio 0.42 |
2003 - Ryan et al. (IAUC 8128) |
? |
36.57 hr |
Vesta family |
|
4674 Pauling |
S/2004 (4674) 1 |
8 et 2.5 Km (# 2.5 mag K) |
2004 - Merline et al (IAUC 8297) |
250 |
? |
Hungaria |
|
|
5381 Sekhmet |
S/2003 (5381) 1 |
1000 m and 300 m |
2003 - Nolan (IAUC 8163) |
1.5 |
12 hr |
Aten |
|
|
(17246) 2000 GL74 |
S/2004 (17246) 1 |
4.5 et 2 Km |
2004 - Tamblyn et al (IAUC 8293) |
230 |
? |
Koronis ? |
|
|
26308 1998 SM165 |
S/2001 (26308) 1 |
(# 1.9 mag) |
2001 - Trujillo and Brown (IAUC 7807) |
6000 |
? |
SDO |
|
|
(47171) 1999 TC36 |
S/ 2001 (1999 TC36) 1 |
(# 1.89 mag) |
2001 - Trujillo and Brown (IAUC 7787) |
8000 |
? |
Plutino |
|
|
(58534) 1997 CQ29 |
S/ 2001 (1997 CQ29) 1 |
(# 0.4 mag) |
2001 - Noll et al. (IAUC 7824) |
5200 |
? |
Cubewano |
|
|
(65803) 1996 GT |
S/ 2003 (65803) 1 |
800 m et 150 m |
2003 - Pravec et al. (IAUC 8244) |
? |
11.9 hr |
Amor 2 |
|
|
(66063) 1998 RO1 |
S/ 2003 (66391) 1 |
ratio 0.4 minimum |
2003 - Pravec et al. (MPML 24-Sep-03) |
|
14.53 hr |
Aten |
|
|
(66391) 1999 KW4 |
S/ 2001 (1999 KW4) 1 |
1200 and 400 meters |
2001 - Benner et al. (IAUC 7632) |
? |
17.45 hr |
Aten |
|
|
(66652) 1999 RZ253 |
S/ 2003 (1999 RZ253 ) 1 |
|
2003 - Noll et al. (IAUC 8143) |
6300 |
|
Cubewano |
|
|
(69230) Hermes |
S/ 2003 (1937 UB) 1 |
both ~ 400 m |
2003 - Margot et al. (IAUC 8227) |
150 m |
13.8 hr ? |
Apollo 2 |
|
|
1990 OS |
S/ 2003 (1990 OS) 1 |
300 m and 45 m |
2003 - Ostro et al. (IAUC 8237) |
> 600m |
18 to 24 hr |
Apollo 2 |
|
|
1998 ST27 |
S/ 2001 (1998 ST27) 1 |
min. ratio 1/3 |
2001 - Benner et al. (IAUC 7730) |
4 |
~100 hr |
Aten |
|
|
1998 WW31 |
S/ 2000 (1998 WW31) 1 |
(# 0.4 mag) |
2000 - Veillet (IAUC 7610) |
1.2 arcsec |
? |
Cubewano |
|
|
1999 DJ4 |
S/ 2004 (1999 DJ4) 1 |
420 et 200 m |
2004 - Pravec et al (IAUC8316+8329) |
> 700m |
17.72 h |
Apollo-2 |
|
|
2000 CF105 |
S/2002 (2000 CF105) 1 |
(# 0.87 mag) |
2002 - Noll et al. (IAUC 7857) |
<=23000 |
? |
Cubewano |
|
|
2000 CQ114 |
S/2004 (2000 CQ114) 1 |
( # ~ 0.5 mag ) |
2004 - Stephens et Noll (IAUC 8289) |
5880 Km |
? |
Cubewano |
|
|
2000 DP107 |
S/ 2000 (2000 DP107) 1 |
800 and 300 m (# 2.1 mag) |
2000 - Margot and Nolan (IAUC 7496) |
2.6 km |
42.2 hr |
Apollo 1 |
|
|
2000 UG11 |
S/ 2000 (2000 UG11) 1 |
230 and 100 meters |
2001 - Nolan et al. (IAUC 7518) |
? |
18.4 hr |
Apollo 2 |
|
|
2001 QC298 |
S/ 2002 (2002 QC298) 1 |
? |
2002 - Noll and Stephens (IAUC 8034) |
5000 |
? |
Cubewano |
|
|
2001 QT297 |
S/ 2001 (2001 QT297) 1 |
(# 0.55 mag) |
2001 - Elliot et al. (IAUC 7733) |
0.6 arcsec |
? |
Cubewano |
|
|
2001 QW322 |
S/ 2001 (2001 QW322) 1 |
each 200 km (# 0.4 mag) |
2001 - Kavelaars et al (IAUC 7749) |
130000 km |
4 years |
Cubewano |
|
|
2002 BM26 |
S/ 2002 (2002 BM26) 1 |
600 and 100 meters |
2002 - Nolan et al. (IAUC 7824) |
100 meters |
< 72 hr |
Amor 2 |
|
|
2002 KK8 |
S/2002 (2002 KK8) 1 |
500 and 100 meters |
2002 - Nolan et al. (IAUC 7921) |
? |
? |
Amor 2 |
|
|
2003 SS84 |
S/2003 (2003 SS84) 1 |
120 and 60 meters |
2003 - Nolan et al. (IAUC 8220) |
? |
23.99 hr |
Apollo 2 |
|
|
2003 UN284 |
S/2003 (2003 UN284) 1 |
(# 0.59 mag) |
2003 - Millis and Clancy (IAUC 8251) |
2.0 arcsec |
? |
Cubewano |
|
|
2003 YT1 |
S/2004 (2003 YT1) 1 |
1000 et 180 mètres |
2003 -Nolan et al (IAUC 8336) |
? |
30 h |
Apollo-1 |
|
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|
Other asteroids judged to be binary ( by radar, Hubble, occultations, lightcurves - NB: list not complete) |
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Asteroid |
Orbital period in hr |
Family |
Discoverers of probable binary nature |
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|
|
7 Iris |
? |
Belt N°1 |
1995 - Mitchell et al. |
Radar |
|
|
|
12 Victoria |
? |
Belt N°1 |
1995 - Mitchell et al. |
Radar |
|
|
|
15 Eunomia |
? |
Belt N°1 |
1985 - Cellino et al. |
Sep. 0.26 arcsec and # 1.0 mag |
|
|
18 Melpomene |
? |
Belt N°1 |
Fernbank Observatory, USA |
Satellite of 48 km at 750 km ? |
|
|
39 Laetitia |
? |
Belt N°1 |
1985 - Cellino et al. |
Sep. 0.13 arcsec and # 0.8 mag |
|
|
43 Ariadne |
? |
Belt N°1 |
1985 - Cellino et al. |
Sep. 0.10 arcsec and # 0.6 mag |
|
|
44 Nysa |
? |
Belt N°1 |
1985 - Cellino et al. |
Sep. 0.08 arcsec and # 1.4 mag |
|
|
49 Pales |
? |
Belt N°1 |
Tedesco |
Satellite of 50 km at 450 km ? |
|
|
61 Danae |
? |
Belt N°1 |
1985 - Cellino et al. |
Sep. 0.07 arcsec and # 1.5 mag |
|
|
82 Alkmene |
? |
Belt N°1 |
1985 - Cellino et al. |
Sep. 0.05 arcsec and # 1.1 mag |
|
|
129 Antigone |
? |
Belt N°1 |
1977 - Scaltriti and Zapalla |
Sep. 0.05 arcsec and # 1.7 mag |
|
|
146 Lucina |
? |
Belt N°1 |
Arlot et al. |
During occultation |
|
|
|
164 Eva |
? |
Belt N°1 |
Schober et al. |
During occultation |
|
|
|
171 Ophelia |
? |
Belt N°1 |
Tedesco |
Satellite of 30 km at 300 km ? |
|
|
216 Kleopatra |
? |
Belt N°1 |
Cellino (1985) and Marchis(IAUC 7308) |
Sep. 0.17 arcsec and # 0.2 mag |
|
|
287 Nephthys |
? |
Belt N°1 |
Marchis et al ( via BDL ) |
Satellite at 111 km ? |
|
|
|
361 Bononia |
? |
Hilda |
Roger Venable ( 01/2002 ) |
During occultation |
|
|
|
532 Herculina |
? |
Belt N°1 |
James McMahon |
Satellite of 50 km at 1000 km ? |
|
|
624 Hektor |
|
Trojan-East |
Cellino et al. (1985) |
Sep. 0.08 arcsec and # 0.1 mag |
|
|
772 Tanete |
? |
Belt N°1 |
IOTA (MPML 24/04/04) |
Satellite of 40km at 1200 km ? ( Occult.18-Apr-04 ) |
1089 Tama |
0.6852 |
Belt N°1 |
Roy and Behrend (IAUC 8265) |
Sép. 0"03 ( 20 km ) and # 0.5 mag ( ratio 0.7 ) |
|
1313 Berna |
1.061 |
Belt N°1 |
Roy and Behrend (IAUC 8292) |
Sép. 0"03 and # 0.7 mag |
|
|
3671 Dionysus |
27.72 |
Amor 3 |
Mottola and Hahn (IAUC 6680) |
|
|
|
4492 Debussy |
? |
Belt N°1 |
Behrend et al (AUDE 21/03/04) |
Eclipse of 0.5 mag |
|
|
|
5407 1992 AX |
(13.52) |
Mars-crosser |
Petr Pravec et al. |
|
|
|
31345 1998 PG |
(14.01) |
Amor 2 |
Petr Pravec et al. |
|
|
|
35107 1991 VH |
32.69 |
Apollo 1 |
P. Pravec and G. Hahn |
|
|
|
1994 AW1 |
22.40 |
Amor 1 |
Petr Pravec et al. |
|
|
|
1996 FG3 |
16.14 |
Apollo 1 |
Petr Pravec et al. |
|
|
|
1999 HF1 |
14.02 |
Aten |
Petr Pravec (MPML 0-Mar-02) |
|
|
|
2001 SL9 |
16.40 |
Apollo 1 |
Petr Pravec et al. |
|
|
|
2003 QY90 |
? |
SDO |
J.L.Elliot et al. (IAUC 8235) |
Sep. 0.34 arcsec / Pair unresolved |
|
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|
|
|
|
|
NB: 15 to 17% of NEAs larger than 200 m across might be binary asteroids. |
|
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|
Currently, binary asteroids appear to be less numerous amongst TNOs, and even less so in the Belt N°1 than amongst NEAs ( Harris - MPML 23-Nov-03) |
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|
|
Asteroids having companions would have different rotation periods according to orbital type ( Petr Pravec - MPML 20-Feb-03 ) : |
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- 4 to 6 hours for Main-belt objects with an average amplitude of 0.4 mag. |
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|
- 2 to 4 hours for Earth-crossers with a lower average amplitude of 0.1 mag. |
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Taxonomic distribution of asteroids |
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A little more than 2000 asteroids have had their taxonomic type determined, thanks to spectral analysis. |
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All of the various taxonomic types that exist have not yet been identified and their distribution as a function of their average distance from the Sun is still uncertain, |
|
|
however two large groups dominate : |
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|
1) Asteroids of type S, covered with silicates, mainly in the inner part of the Belt N°1, and more than 30 km in diameter. |
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|
They represent around 20% of Main-belt objects. Small objects of type S find their way in virtually any part of the Belt N°1. |
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2) Asteroids of type C, carbonaceous and very dark, numerous starting from the outer region of the Belt N°1, and representing 56% of the |
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|
Main-belt population. |
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|
- Various taxonomic types, combined in Group X, which comprises 24% of the population of the Belt N°1. |
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A new factor influencing the surface properties of asteroids has been recently introduced, namely the "space weathering process". |
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|
It is manifest as a phenomenon which alters asteroid surfaces through being subjected to aggressive ultraviolet solar radiation and |
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|
cosmic rays. |
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This process darkens asteroid surfaces, increasing the reddening of their spectra. |
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Recent "fragments" of S-type asteroids would in this way become Q-type asteroids having surfaces newly-exposed to solar radiation and space. |
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The albedo of NEAs of type S increase on average with decreasing diameter. |
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The spectral differences of NEAs should enable one to identify those that have resulted from recent ejection from the v6 and 3:1 resonances and which have |
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spent a very long time exposed to the Sun whilst transferring via the Mars-crossers to the region of the Earth's orbit. |
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There is a greater spectral diversity among the small asteroids than for the large asteroids, which by contrast seem to show sometimes different spectral types |
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to their surface. |
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Beyond 3.2 AU from the Sun, the vast majority of asteroids have a very low albedo, but some notable exceptions do exist such as the albedos of |
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Pluto or of 2060 Chiron. |
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The Jupiter-Trojans and more distant asteroids are expected to be rich in water ice and volatile materials. |
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Their primordial constitution does not seem to have evolved much, except for their surface seeming to be made up of organic-complex solid material. |
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Jupiter-Trojans are characterised by surfaces having unremarkable reddish spectra with low albedos. |
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All Trojans of Jupiter are of spectral type D. |
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The spectra of Centaurs indicate the existence of various surface types characteristed by their very different spectral colours, from very red as with 5145 Pholus |
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to neutral as for 2060 Chiron which does not possess any dark irradiated coating. |
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Their spectral characteristics appear to approach those of the TNOs, indicating their probable origin in the Kuiper Belt. |
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Kuiper-belt objects should be composed of ices of H2O, CO, CO2 and of dust. |
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On going from the Centaur to the SKBO, there doesn't appear to be any marked change in the distribution of different spectral types as a function of distance from the |
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Sun, except for a reddening of surface colour. |
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Therefore, some TNO or Centaur objects show different colours which seem to arise from differently-combined actions altering the surface as well as |
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the action of impacts causing the appearance of sub-surface layers on TNOs. |
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Around 1/3 of the surface of 100-km TNOs would have been remodelled by impacts during the last 3.5 billion years. |
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The Plutinos would have been more affected by collisions, as there are very few of them with a bluish spectrum characteristic of the primordial TNO surface. |
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Current mineralogical types of asteroids and their albedo |
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Type |
Albedo |
Type of surface |
Associated Meteorites |
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A |
0.13 - 0.40 |
Rich in Olivine |
Brachina |
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B |
0.04 - 0.08 |
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Carbonaceous Chondrites ? |
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C |
0.03 - 0.07 |
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Carbonaceous Chondrites (CM) |
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D |
0.02 - 0.05 |
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Kerogenes ? |
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E |
0.25 - 0.60 |
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Aubrites |
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F |
0.03 - 0.06 |
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G |
0.05 - 0.09 |
|
Carbonaceous Chondrites ? |
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M |
0.10 - 0.18 |
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Enstatite Chondrites, Iron |
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P |
0.02 - 0.06 |
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Q |
~ 0.20 |
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Ordinary chondrites unaltered by space weathering |
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R |
~ 0.40 |
Rich in Olivine |
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S |
0.10 - 0.22 |
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Iron-rich and ordinary Chondrites having suffered aging in space |
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T |
0.04 - 0.11 |
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V |
~ 0.40 |
Rich in Pyroxene |
Basaltic Achondrites ( HED ) |
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A new 2002 classification of mineralogical types for asteroids |
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At the end of 2002, a new spectral classification was established following some intensive CCD work. This is still in the process of analysis by the experts. |
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This classification arose from the SMASS II survey of Bus and Binzel indicating the existence, in the Belt N°1 of 3 large groups S, C and X, and some small |
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groups having very specific spectral signatures. |
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Group X is made up of sub-groups that cannot be classed in groups S and C, but spectrally is situated between S and C. |
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The subdivision of these groups depending on spectral particulars within the groups has given rise to a splitting into 26 different spectral |
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classes (or types) for the 1343 asteroids studied, with semi-major axes located from 2.10 to 3.78 AU : |
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Group S = Types A, K, L, Q, R, S, Sa, Sk, Sl, Sq and Sr |
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Group C = Types B, C, Cb, Cg, Cgh and Ch |
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Group X = Types X, Xc,Xe and Xk |
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Unusual Objects = Types D, Ld, O, T and V |
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Types Sa, Sk, Sl, Sq, Sr, Cb, Cg, Cgh, Ch, Xc, Xe and Xk have spectral types which are in part similar to other neighbours designated by lower-case suffixes. |
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They also correspond to an extent with the letters used previously, based on the older spectral analyses. |
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The previous asteroids of type E, M and P are reallocated in the different types within Group X . |
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The previous asteroids of type G and F are now assigned to the different types of Group C . |
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Other spectral classes will be added in the future to represent those very specific groups many of which will be further than the Belt N°1, such as |
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the class of very reddened asteroids ( e.g. 5145 Pholus ) |
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Among the very specific types studied under SMASS II, there are : |
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- Asteroids of surface-type V, generally members of the Vesta dynamic family. Some cases more distant than 4 Vesta are known : 956 Elisa, |
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the Floras 809 Lundia and 4278 Harvey, and 1459 Magnya situated in the outer region of the Belt N°1. |
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- Type O only has 4 members known : 3628 Boznemcova, 4341 Poseidon, 5341 Herakles and 1997 RT. |
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- the R spectral class also is represented by only 4 asteroids : 349 Dembowska, 1904 Massevitch, 2371 Dimitrov and 5111 Jacliff |
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- 1862 Apollo is the lead example of type Q comprising a dozen Earth-crossers. No minor planet from the Belt N°1 falls in this class. |
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- Objects of type K make up nearly one-half of the "Eos" dynamical family. |
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Mineralogical types for asteroids according to the new 2002 classification and their albedo |
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Type |
Albedo |
Type of surface |
Associated Meteorites |
Remarks |
|
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A |
0.13 to 0.40 |
Rich in Olivine |
Brachina |
Belonging to fragmented objects ? |
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B |
0.04 to 0.08 |
|
Carbonaceous Chondrites ? |
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|
C |
0.03 to 0.09 |
|
Carbonaceous Chondrites (CM) |
Notably the Themis and Hygiea families |
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D |
0.02 to 0.05 |
cometary material ? |
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Jupiter-Trojans and beyond |
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K |
~ 0.10 ? |
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especially the Eos family |
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O |
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Ordinary Chondrites L6 and LL6 |
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Q |
~ 0.20 |
Rich in Pyroxene |
Ordinary Chondrites L4 and LL5 |
Currently only Earth-crossers |
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R |
~ 0.40 |
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S |
0.10 to 0.22 |
|
Iron-rich and ordinary Chondrites |
Floras and Eunomias notably |
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T |
0.04 to 0.11 |
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V |
~ 0.40 |
|
Basaltic Achondrites ( HED ) |
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Xe |
0.25 to 0.60 |
presence of Troilite |
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Hungarias and inner edge of Belt N°1 |
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X ( ex-M ) |
0.10 to 0.18 |
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Enstatite Chondrites, Iron, Nickel |
cores of fragmented asteroids ? |
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NB: The links between the taxonomic and mineralogical types are not yet perfectly established so that one (current) spectral class perhaps may not be representative of |
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a specific mineralogy. |
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Small asteroids and recently-created Earth-crossers can have more varied mineralogical types being less altered (over time) than the larger asteroids, which, themselves, |
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can represent varied mineralogies, considering the more significant surface types ( e.g. 64 Angelina and 434 Hungaria ). |
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Asteroids already visited by probes from Earth |
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Asteroid |
Encounter Date |
Probe |
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951 Gaspra |
29-Oct-1991 |
Galileo |
Flypast at 1600 km |
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243 Ida |
28-Aug-1993 |
Galileo |
Flypast at 2400 km, and discovery of Dactyl |
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253 Mathilde |
27-Jun-1997 |
NEAR |
Flypast at 1212 km |
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9969 Braille |
29-Jul-1999 |
Deep Space 1 |
Flypast at about 26 km, 'blind' |
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433 Eros |
23-Dec-1998 |
NEAR |
Flypast at 3830 km |
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2685 Masursky |
23 janvier 2000 |
Cassini |
Flypast at 1.6 million km |
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433 Eros |
Arrival 14-Feb-2000 |
NEAR-Shoemaker |
12-Feb-2001 : Landing of the probe on Eros |
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5535 Annefrank |
02-Nov-2002 |
Stardust |
Flypast at 3300 km |
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Future explorations of asteroids by terrestrial space probes |
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Asteroids |
Mission leaves |
Probes |
Flypast date |
H |
Zone |
Remarks |
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25143 Itokawa |
May 2003 |
Muses-C ( ISAS - Japan ) |
Summer 2005 : 4.5 months + samples |
19.2 |
Apollo 1 |
(ex -1998 SF36) |
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21 Lutetia |
March 2004 |
Rosetta ( ESA ) |
10 July 2010 |
7.35 |
Main Belt |
type Xk (ex-M) |
|
2867 Steins |
MArch 2004 |
Rosetta ( ESA ) |
05 September 2008 |
13.19 |
Main Belt |
type S (IAUC 8315) |
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Pluto-Charon |
January 2006 |
New Horizons ( NASA ) |
2015 : duration 6 months |
- 1.6 |
Plutinos |
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|
TNO |
January 2006 |
New Horizons ( NASA ) |
not yet chosen |
? |
? |
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|
1 Ceres |
May 2006 |
Dawn ( NASA ) |
Arrival in 2014 |
3.34 |
Belt N°1 |
C |
|
|
4 Vesta |
May 2006 |
Dawn ( NASA ) |
Arrival in 2010 - 1 year in orbit |
3.20 |
Belt N°1 |
V |
|
|
Main-belt Asteroids |
May 2006 |
Dawn ( NASA ) |
not yet chosen |
? |
Belt N°1 |
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Near-Earth asteroids which can be most easily visited by space probes |
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Between now and 2013, 27 NEAs approaching very close to the Earth could be easily visited, of which 5 have very low launch costs, plus two others of great interest : |
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Asteroid |
Family |
Flypast date possible |
Specifics |
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1996 FG3 |
APOLLO 1 |
|
H = 18.2 - Probable binary asteroid, of type C |
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1996 XB27 |
AMOR 1 |
2004 or 2005 |
H = 22.0 - 200 meters across |
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25143 Itokawa |
APOLLO 1 |
|
H = 19.2 - 690x300 meters in size = Target for MUSES-C |
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|
1998 KY26 |
APOLLO 1 |
2011 or 2013 |
H = 25.5 - 30 meters across |
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Rotation period : 11 min / Carbonaceous Chondritic surface |
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1999 AO10 |
ATEN |
January 2006 or April 2007 |
The most accessible |
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2000 EA14 |
APOLLO 1 |
|
H = 20.9 - 320 meters diameter |
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2001 CQ36 |
ATEN |
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H = 22.6 - 150 meters across |
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The most successful numbered Asteroid Discoverers as of 20-May-2004 |
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From 1801 up to 1891, all minor planet discoveries were visual discoveries ! |
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The greatest visual Discoverer was the Austrian professional astronomer, Johann Palisa, with 122 discoveries, some of which were of magnitude 15, at a |
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time when star atlases were virtually non-existent. |
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From 1891, starting with the discovery of 323 Brucia, up until the 1990s, the period of photographic discovery replaced visual discovery. |
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The German professional astronomers, Max Wolf and Karl Reinmuth were the first great photographic discoverers, with respectively 228 |
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and 395 asteroids, when discovery follow-up was still not very easy. |
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Later, C. J. van Houten, I. van Houten-Groeneveld and Tom Gehrels became great photographic discoverers with to this day 3232 |
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discoveries made as part of the "Palomar-Leiden Survey" of 1960 ( Objects PLS ) and of the three "Palomar Trojan Surveys" ( Objects T-1, T-2, T-3 ). |
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Working during both the photographic and CCD periods, Eric Elst has to date been the greatest individual discoverer of Asteroids, with 2979 |
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discoveries and 69 co-discoveries. |
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The current period of CCD cameras and the introduction of powerful automated telescopes has permitted a virtual explosion in the number of discoveries : |
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3524 objets for NEAT, 4169 for Spacewatch, 4238 for LONEOS and 40515 for LINEAR on May 20,2004 !! |
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Amateurs equipped with CCDs have not been idle despite their more modest means. |
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The most prolific are the Japanese T.Kobayashi with 2117 discoveries until 1991, the Croatian Korado Korlevic with 881 asteroids + 99 co-discoveries |
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and the two Japanese duos K. Endate - K. Watanabe ( 691 discoveries ) and Ueda - Kaneda ( 559 discoveries ) . |
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The 12 greatest discoverers and their total discoveries as of 06-May-04 are ( Source MPC ) : |
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LINEAR |
40515 |
|
Automated Observatory |
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USA |
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LONEOS |
4238 |
|
Observatoire automatisé |
|
USA |
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Spacewatch |
4169 |
|
Observatoire automatisé |
|
USA |
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NEAT |
3524 |
|
Observatoire automatisé |
|
USA |
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Van Houten and Gehrels |
3232 |
|
Professional Observatory |
|
Holland - USA |
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Elst |
2979 |
+ 69 co-découvertes |
Professional Observatory |
|
Belgium |
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NEAT |
2117 |
+ 2 co-découvertes |
Automated Observatory |
|
USA |
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Kobayashi |
1511 |
|
Amateur |
|
Japan |
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CSS |
1143 |
+ 287 co-découvertes |
Professional Observatory |
|
USA |
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Bus |
881 |
+ 99 co-découvertes |
Professional Observatory |
|
USA |
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Korlevic |
691 |
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Amateur |
|
Croatia |
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UESAC |
881 |
|
Professional Observatory |
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Sweden |
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Ueda and Kaneda |
691 |
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Amateurs |
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Japan |
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SOURCES AND REFERENCES |
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Ref. G.Faure |
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P.B. Babadzhanov |
Meteor showers associated with the near-Earth asteroid (2101) Adonis - Astronomy Astrophysics 397, 310-323 (2003) |
<GF:pc> |
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|
M.A.Barucci et al. |
Physical Properties of Trojan and Centaur Asteroids - Asteroids III |
|
<GF:web> |
|
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|
J.M.Bauer et al |
Physical survey of 24 Centaurs with visible photometry - Icarus 166 (2003) 195-211 |
|
<GF:qt> |
|
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|
|
C.Beaugé / F.Roig |
A semianalytical Model for the Motion of the Trojan Asteroids: Proper Elements and Families - Icarus 153, 391-415 (2001) <GF:mc> |
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J.Kelly Beatty |
Kalliope's Kin (News Note) - Sky and Telescope January 2002 page 20 |
|
<GF:md> |
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Raoul Behrend |
Website of lightcurves ( http://obswww.unige.ch/~behrend/page_cou.html ) |
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P. Bendjoya |
A classification of 6479 asteroids into families by means of the wavelet clustering method |
|
<GF:bu> |
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(Astronomy and Astrophysics Supplement Series 102, 25-55 - November 1993) |
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Jérôme Berthier |
List of binary asteroids ( http://www.bdl.fr/observateur/binast/binary_ast.php ) |
|
- |
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Franck Bertoldi |
Measurements of the diameters of the large KBOs by IRAM ( http://www.mpifr-bonn.mpg.de/staff/bertoldi/kbo/pr_kbo_e.html ) |
- |
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Richard P. Binzel |
A new century for asteroids - Sky and Telescope Jul-2001 pages 44 to 51 |
|
<GF:lw> |
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Richard P. Binzel |
Discovery of spin vector alignments: A triumph for asteroid lightcurve observers - Minor Planet Bulletin Vol 31, N° 1 |
|
- |
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|
William Bottke et al. |
Debiased Orbital and Absolute Magnitude Distribution of the Near-Earth Objects - Icarus 156, 399-433 (2002) |
|
<GF:oz> |
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|
|
A.Brunini / M.D.Mellita |
The Existence of a Planet beyond 50 AU and the Orbital Distribution of the Classical Edgeworth-Kuiper-Belt objects |
|
<GF:oj> |
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|
Icarus 160, 32-43 (2002) |
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A.Brunini et al |
Cratering rate on the jovian system : the contribution from Hilda asteroids - Icarus 165 (2003) 371- 378 |
|
<GF:rc> |
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S.J.Bus / R.P. Binzel |
Phase II of the Small Main-Belt Asteroid Spectroscopic Survey - A Feature-Based Taxonomy |
|
<GF:pa> |
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|
Icarus 158, 146-177 (2002) |
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Matthias Busch |
Die verschiedenen Gruppen von Kleinplaneten (http://home.t-online.de/home/matthias.busch/screenshots/index.htm ) |
- |
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|
E.I. Chiang et al. |
Resonant and secular Families of the Kuiper Belt - http://astron.berkeley.edu/~echiang/ppp/ppp.html |
|
- |
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|
M-A Combes/ J.Meeus |
"Nouvelles des Earth-Grazers" N° 0 to 8 - L'Astronomie from 1974 to 1991 |
|
- |
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|
M-A Combes/ J.Meeus |
"Chronique des objets A.A.A." N° 1 à 19 ( Observations et travaux - Années 1992 à 1997 ) |
|
- |
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Michel-Alain Combes |
"La menace du ciel" ( http://astrosurf.com/macombes ) |
|
- |
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|
Apostolos Christou |
The nearest of Near Earth Asteroids ( http://star.arm.ac.uk/~aac/astrodyn.html ) |
|
- |
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|
C.L. Dandy et al. |
Optical colors of 56 near-Earth objects: trends with size and orbit |
|
<GF:qo> |
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|
John Davies et al. |
The lightcurve and colors of Unusual Minor Planet 1998 WU24 - Icarus 150, 69-77 (2001) |
|
<GF:mp> |
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M. Delbo et al |
Keck observations of near-Earth asteroids in the thermal infrared - Icarus 166 (2003) 116-130 |
|
<GF:qu> |
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C. De Berg / J. Romon |
Les objets de Kuiper - L'Astronomie Vol.115, January/February 2001 pages 78-89 |
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- |
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Dell'Oro et al. |
The role of Families in Determining Collision Probability in the Asteroid Belt N°1 - Icarus 153, 52-60 (2001) |
|
<GF:mb> |
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A. Doressoundiram et al. |
Multicolor Photometry of Trans-Neptunian Objects - Icarus 154, 277-286 (2001) |
|
<GF:pd> |
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Daniel D. Durda et al. |
A new Observational Search for Vulcanoids in SOHO/LASCO Coronograph images - Icarus 148, 312-315 (2000) |
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<GF:mi> |
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Eric Elst |
On the discovery of faint Trojans ( http://www.astro.hr/mace2002/abstracts/abstracts.html ) |
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Gérard Faure |
Private Databases and statistical works On Asteroids |
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Marcos Florczak et al. |
A Visible Spectroscopic Survey of the Flora Clan - Icarus 133, 233-246 (1998) |
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Marcos Florczak et al. |
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<GF:oc> |
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Cr. and Cl Froeschle |
Les astéroides - La Recherche N°183 - December 1986 |
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<GF:PU> |
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Gabryszewski/Wlodarczyk |
The resonant dynamical evolution of small body orbits among giant planets |
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<GF:qa> |
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Astronomy and Astrophysics 405, 1145-1151 (2003) |
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Alessandro Giuntini |
Twice than expected ( Tumbling stone - Issue 13 - http://spacegAUrd.ias.rm.cnr.it/tumblingstone/issues/ ) |
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J.C.Gradie et al. |
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<GF:FM> |
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Bill Gray |
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<GF:lb> |
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Bernard Guillaud-Saumur |
Orbital elements of comets ( http://www.astrobgs.dyndns.org/astro/cmt2004/comet.txt) |
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Alan W. Harris |
Asteroid Lightcurve Catalog ( http://cfa-www.harvard.edu/iau/lists/LightcurveDat.html ) |
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W.K. Hartmann |
Current, Unusual Asteroids Models ( Table I ) - Asteroids (Gehrels - 1979) |
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<GF:JX> |
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IAA - Russie |
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IAUC |
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A.M. |
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B.Gladman et al. |
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<GF:ng> |
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Alan W. Harris |
"On the Slow Rotation of Asteroids" - Icarus 156, 184-190 (2002) |
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<GF:nw> |
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P.M.Janiczek et al. |
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R.Jedicke / T.Metcalfe |
The Orbital and Absolute Magnitude Distributions of Belt N°1 Asteroids - Icarus 131, 245-260 (1998) |
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<GF:kl> |
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R.Jedicke et al. |
Observational Selection Effects in Asteroid Surveys and Estimates of Asteroid Population Sizes - ( Asteroids III ) |
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<GF:web> |
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David Jewitt |
The Kuiper Belt ( http://www.ifa.hawai.edu/~jewitt/kb.html ) |
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M.Kelley / M.Gaffey |
"9 Metis and 113 Amalthea: A Genetic Asteroid Pair" - Icarus 144, 27-38 (2000) |
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<GF:lr> |
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Z. Knezevic / A. Milani |
Proper elements catalogs and asteroid families - Astronomy and Astrophysics 403, 1165-1173 (2003) |
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<GF:ql> |
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Y.Kozai |
Dynamics of families - Asteroids ( Gehrels -1979 ) |
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A. Kryszczynska et al. |
Puzzling rotation of asteroid 288 Glauke - Astronomy and Astrophysics 404, 729-733 (2003) |
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<GF:pz> |
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H.Levison / A.Morbidelli |
Forming the Kuiper Belt by the Outerward Transport of Objects During Neptune's Migration - Nature November 27,2003 |
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F. Marzari et al. |
Collisional Evolution of Asteroid Families - Icarus 113,168-187 |
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F. Marzari et al. |
Origin, Aging, and Death of Asteroid Families - Icarus 142, 63-77 |
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<GF:lp> |
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Gianluca Masi |
Searching for inner-Earth Objects: a possible ground-based approach - Icarus 163, 389-397 (2003) |
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<GF:qp> |
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Jean Meeus |
An Asteroid's Remarkable orbit - Sky and Telescope, December 1997 |
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<GF:ig> |
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W.Ip / R.Mehra |
Resonances and librations of some Apollo and Amor asteroids with the Earth - The Astron. J., Vol 78, N° 1 (Feb-1973) |
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P.Michel / P.Tanga et al. |
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<GF:od> |
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Reaccumulation - Icarus 160, 10-23 (2002) |
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T.A. Michtchenko et al. |
Origin of the Basaltic Asteroid 1459 Magnya: A Dynamical and Mineralogical Study of the Outer Belt N°1 |
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<GF:oi> |
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Icarus 158, 343-359 (2002) |
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A.Milani / P.Farinella |
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<GF:kf> |
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Minor Planet Center |
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Files of asteroid orbital elements ( http://cfa-www.harvard.edu/pub/MPCORB/ ) |
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Minor Planet Mailing List |
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M.Morais / A.Morbidelli |
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A. Morbidelli et al. |
From Magnitudes to Diameters: The Albedo Distribution of Near Earth Objects and the Earth Collision Hazard |
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<GF:oh> |
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Icarus 158, 329-342 (2002) |
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A. Morbidelli et al. |
The shallow magnitude distribution of asteroid families - Icarus 162, 328-336 (2003) |
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<GF:pw> |
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A. Morbidelli / H. Levison |
Scenarios for the Origin of the Orbits of the Trans-Neptunian Objects 2000 CR105 and 2003 VB12 |
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<GF:qw> |
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Astrophysics, abstract astro-ph/0403358 |
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Morbidelli/Vokrouhlicky |
The Yarkovsky-driven origin of near-Earth asteroids - Icarus 163, 120-134 (2003) |
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<GF:qk> |
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T. Mothé-Diniz et al. |
Distribution of taxonomic classes in the Belt N°1 of asteroids - Icarus 162, 10-21 (2003) |
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<GF:px> |
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NASA |
Asteroid and Comet Impact Hazards (http://impact.arc.nasa.gov/reports/spaceguard/sg_5.html) |
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<GF:jj> |
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D.Nesvorny et al. |
The Recent Breakup of an Asteroid in the Main-Belt Region ( http://www.swri.org/9what/releases/15asteroid.htm ) |
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MPML 13-Jun-02 |
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D.Nesvorny et al. |
The Flora Family : A Case of the Dynamically Dispersed Collisional Swarm ? - Icarus 157, 155-172 (2002) |
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<GF:nf> |
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D.Nesvorny / L.Dones |
How long-Lived Are the Hypothetical Trojan Populations of Saturn, Uranus and Neptune ? - Icarus 160, 271-288 ( 2002 ) |
<GF:ol> |
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Joel Parker |
The Kuiper Belt Electronic Newsletter - http://www.boulder.swri.edu/ekonews/ |
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Jason Perry |
http://members.fortunecity.com/volcanopele/Moon_list.htm (Jason Perry - MPML 01-Apr-01) . |
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J-M.Petit / A.Morbidelli |
The primordial excitation and clearing of the Asteroid Belt- Icarus 153, 338-347 (2001) |
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<GF:ma> |
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Petr Pravec et al. |
Fast Rotating Asteroids: 1999 TY2, 1999 SF10 and 1998 WB2 - Icarus 147, 477-486 (2000) |
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<GF:mo> |
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P.Pravec / A.W.Harris |
Fast and Slow Rotation of Asteroids - Icarus 148, 12-20 (2000) |
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<GF:mk> |
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Petr Pravec |
Binary Near-Earth Asteroids ( http://www.asu.cas.cz/~asteroid/binneas.htm ) |
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A.S. Rivkin et al |
Spectroscopy and photometry of Mars Trojans - Icarus 165 ( 2003) 349-354 |
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<GF:ra> |
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Sylvain Rondi et al. |
Les troyens du système solaire ( http://dess-s2.obspm.fr/~rondi/3c/menu.htm ) |
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Petr Scheirich |
Asteroid Groups ( http://sajri.astronomy.cz/asteroidgroups/groups.htm ) |
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Brian Skiff |
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S.M.Slivan et al. |
Spin vectors in the Koronis family: comprehensive results from two independent analyses of 213 lightcurves |
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<GF:pm> |
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Icarus 162, 285-307 (2003) |
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David Tholen |
Personal communication ( E-message of 15-Apr-2002 ) |
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J. Toth / L. Kornos |
Close approaches of Very Small Near Earth Objects and their possible detection in the Earth-Moon vicinity |
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<GF:pb> |
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( Acta Astron. et Geophys. Univ. Comenianae XXIV, 61-70 (2002) ) |
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K.Tsiganis et al |
Short-lived asteroids in the 7/3 Kirkwood gap and their relationship to the Koronis and Eos families |
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<GF:rd> |
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J. Virtanen et al. |
Orbit computation for transneptunian objects - Icarus 161, 419-430 (2003) |
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D.Vokrouklicky et al. |
The Depletion of the Putative Vulcanoid Population via the Yarkovsky Effect - Icarus 148, 147-150 (2000) |
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<GF:mj> |
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Brian Warner |
CALL homepage ( http://www.MinorPlanetObserver.com/astlc/default.htm ) |
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Five brightest Apparitions of numbered Asteroids ( http://www.MinorPlanetObserver.com/htms/FiveBrightest.html ) |
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Richard M. Williamson |
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V.Zappala et al. |
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Asteroid families: Search of a 12487 Asteroid Sample Using two Different Clustering techniques |
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Icarus 116, 291-314 (1995) |
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B.Zellner et al. |
The Large-scale Structure of the Asteroid Belt - Icarus 62, 505-511 (1985) |
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<GF:LQ> |
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? |
The real Asteroid Belts ( News Notes) - Sky and Telescope, March 1986 |
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<GF:NO> |
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