List of exceptional asteroids

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Ceres is the largest and most massive asteroid and the only one that is a dwarf planet.
Vesta is the brightest and second-most-massive asteroid. It suffered a crust-penetrating impact approximately one billion years ago.[1]

The following is a collection of lists of exceptional asteroids in the Solar System. For the purposes of this article "asteroid" means minor planet up to the orbit of Jupiter, which includes the dwarf planet Ceres. For a complete list of minor planets in numerical order, see List of minor planets.

Note: each asteroid is given a unique sequential identifying number after its orbit is precisely determined. Prior to this, asteroids are known only by their systematic name or provisional designation, such as "1950 DA".

Physical characteristics[edit]

Largest by diameter[edit]

Estimating the sizes of asteroids from observations is difficult due to their irregular shapes, varying albedo (reflectivity), and small angular diameter. For example pure C-type asteroids are much darker than most. Asteroids with only one or two axes measured may have a falsely inflated geometric mean diameter if the unknown second and/or third axis is noticeably smaller than the primary axis. Asteroid 16 Psyche has an IRAS diameter of 253 km, yet has a more recent and accurate geometric mean of only 186 km.

Name Diameter (km)
(geometric mean)
Dimensions (km) Mean distance
from Sun (in AU)
Date discovered Discoverer Class
0011 Ceres 946±2 965×962×891 2.766 January 1, 1801 Piazzi, G. G
0022 Pallas 544±18 582×556×500 2.773 March 28, 1802 Olbers, H. W. B
0044 Vesta 525.4±0.2 572.6 × 557.2 × 446.4 ± 0.2 2.362 March 29, 1807 Olbers, H. W. V
01010 Hygiea 431±7 530×407×370 3.139 April 12, 1849 de Gasparis, A. C
704704 Interamnia 326 350×304 3.062 October 2, 1910 Cerulli, V. F
05252 Europa 315 380×330×250 3.095 February 4, 1858 Goldschmidt, H. C
511511 Davida 289 357×294×231 3.168 May 30, 1903 Dugan, R. S. C
08787 Sylvia 286 385×265×230 3.485 May 16, 1866 Pogson, N. R. X
06565 Cybele 273 302×290×232 3.439 March 8, 1861 Tempel, E. W. C
01515 Eunomia 268 357×255×212 2.643 July 29, 1851 de Gasparis, A. S
0033 Juno 258 320×267×200 2.672 September 1, 1804 Harding, K. L. S
03131 Euphrosyne 256 3.149 September 1, 1854 Ferguson, J. C
624624 Hektor 241 370×195(×195) 5.235 February 10, 1907 Kopff, A. D
08888 Thisbe 232 221×201×168 2.769 June 15, 1866 Peters, C. H. F. B
324324 Bamberga 229 2.684 February 25, 1892 Palisa, J. C
451451 Patientia 225 3.059 December 4, 1899 Charlois, A.
532532 Herculina 222 2.772 April 20, 1904 Wolf, M. S
04848 Doris 222 278×142 3.108 September 19, 1857 Goldschmidt, H. C
375375 Ursula 216 3.126 September 18, 1893 Charlois, A.
107107 Camilla 215 285×205×170 3.476 November 17, 1868 Pogson, N. R. C
04545 Eugenia 213 305×220×145 2.720 June 27, 1857 Goldschmidt, H. F
0077 Iris 213 240×200×200 2.386 August 13, 1847 Hind, J. R. S
02929 Amphitrite 212 233×212×193 2.554 March 1, 1854 Marth, A. S
423423 Diotima 209 171×138 3.065 December 7, 1896 Charlois, A. C
01919 Fortuna 208 225×205×195 2.442 August 22, 1852 Hind, J. R. G
01313 Egeria 206 217×196 2.576 November 2, 1850 de Gasparis, A. G
02424 Themis 198 3.136 April 5, 1853 de Gasparis, A. C
09494 Aurora 197 225×173 3.160 September 6, 1867 Watson, J. C. C
702702 Alauda 195 3.195 July 16, 1910 Helffrich, J.
121121 Hermione 190 268×186×183 3.457 May 12, 1872 Watson, J. C. C
372372 Palma 189 3.149 August 19, 1893 Charlois, A.
128128 Nemesis 188 2.751 November 25, 1872 Watson, J. C. C
0066 Hebe 186 205x185x170 2.426 July 1, 1847 Hencke, K. L. S
01616 Psyche 186 240×185×145 2.924 March 17, 1852 de Gasparis, A. M
120120 Lachesis 174 3.301 April 10, 1872 Borrelly, A. C
04141 Daphne 174 213x160 3.517 May 22, 1856 Goldschmidt, H. C
0099 Metis 174 222x182x130 2.385 April 25, 1848 Graham, A. S

The number of bodies grows rapidly as the size decreases. Based on IRAS data there are about 140 main-belt asteroids with a diameter greater than 120 km.[2] For a more complete list, see List of Solar System objects by size.

The inner asteroid belt (defined as the region interior to the 3:1 Kirkwood gap at 2.50 AU) has few large asteroids. Of those in the above list, only 4 Vesta, 19 Fortuna, 6 Hebe, 7 Iris and 9 Metis orbit there.

Most-massive[edit]

Below are the nineteen most-massive measured asteroids.[3] The masses of asteroids are calculated from perturbations caused by Mars and other asteroids. Different sets of astrometric observations lead to different mass determinations; the biggest problem is accounting for the aggregate perturbations caused by all of the smaller asteroids.[4]

The relative masses of the top twelve asteroids known,[3] compared to the remaining mass of the asteroid belt.[5]
Name Mass
(×1018 kg)
Precision
1 Ceres 939.3 0.05% (939–940)
4 Vesta 259.076 0.0004% (259.075–259.077)
2 Pallas 201 6.4% (188–214)
10 Hygiea 86.7 1.7% (85.2–88.4)
31 Euphrosyne 58.1 34% (38.4–77.8)
704 Interamnia 38.8 4.6% (37.0–40.6)
511 Davida 37.7 5.2% (35.7–39.7)
532 Herculina 33 17% (27–39)
15 Eunomia 31.8 0.9% (31.5–32.1)
3 Juno 28.6 16% (24.0–33.2)
16 Psyche 22.7 3.7% (21.9–23.5)
52 Europa 22.7 7% (21.1–24.3)
88 Thisbe 18.3 6% (17.2–19.4)
7 Iris 16.2 5.6% (15.3–17.1)
13 Egeria 16 27% (12–20)
423 Diotima 16 Unknown
29 Amphitrite 15.2 4% (14.8–15.6)
87 Sylvia 14.78 0.4% (14.72–14.84)
48 Doris 12 50% (6–18)

(All the data above are from Baer et al. 2011, apart from 48 Doris and 532 Herculina, which are Kochetova, 2004.)

Significant uncertainties remain. For example, the uncertainty in the estimate of 31 Euphrosyne is enough for its low end to overlap with both 704 Interamnia and 511 Davida, which overlap each other and also with 532 Herculina, which overlaps with 15 Eunomia and 3 Juno. Juno barely overlaps 52 Europa, which in turn overlaps with 16 Psyche. That is, outside the top four, the order of all the asteroids is uncertain. However, none of the lesser asteroids, of which the most massive are thought to be 88 Thisbe (at 17–19×1018 kg), 7 Iris, 29 Amphitrite and 48 Doris (all in the range of ≈15×1018 kg), overlap with Europa or Psyche, so the first 12 asteroids in the chart above are likely to be the top dozen unless a hitherto unmeasured asteroid proves to be unexpectedly massive.

The largest asteroid with an accurately measured mass, due to the fact that it has been visited by the probe Dawn, is 4 Vesta at 259.076±0.001×1018 kg. The second-largest asteroid with an accurately measured mass, due to the fact that it has a moon, is 87 Sylvia at 14.78±0.06×1018 kg.

For a more complete list, see List of Solar System objects by size. Other large asteroids such as 423 Diotima currently only have estimated masses.[6][7]

Brightest from Earth[edit]

Only Vesta regularly attains a brightness sufficient to be visible to the naked eye. The following asteroids can all reach an apparent magnitude brighter than or equal to the +8.3 attained by Saturn's moon Titan at its brightest, which was discovered 145 years before the first asteroid was found owing to its closeness to the easily observed Saturn.

None of the asteroids in the outer part of the asteroid belt can ever attain this brightness. Even Hygiea and Interamnia rarely reach magnitudes of above 10.0. This is due to the different distribution of spectral types within different sections of the asteroid belt being such that the highest-albedo asteroids are all concentrated closer to Mars, and much lower albedo C and D types being common in the outer belt.

Those asteroids with very high eccentricities will only reach their maximum magnitude on unusual occasions when their perihelion is very close to a heliocentric conjunction with Earth, or (in the case of 99942 Apophis) when the asteroid passes very close to Earth.

Asteroid Magnitude
when
brightest
Semi-major axis (AU) Eccentricity
of orbit
Diameter
(km)
Year of
discovery
99942 Apophis 3.4* 0.922 0.191 0.32 2004
4 Vesta 5.20 2.361 0.089172 529 1807
2 Pallas 6.49 2.773 0.230725 544 1802
1 Ceres 6.65 2.766 0.079905 952 1801
7 Iris 6.73 2.385 0.231422 200 1847
433 Eros 6.8 1.458 0.222725 34 × 11 × 11 1898
6 Hebe 7.5 2.425 0.201726 186 1847
3 Juno 7.5 2.668 0.258194 233 1804
18 Melpomene 7.5 2.296 0.218708 141 1852
15 Eunomia 7.9 2.643 0.187181 268 1851
8 Flora 7.9 2.202 0.156207 128 1847
324 Bamberga 8.0 2.682 0.338252 229 1892
1036 Ganymed 8.1 2.6657 0.533710 32 1924
9 Metis 8.1 2.387 0.121441 190 1848
192 Nausikaa 8.2 2.404 0.246216 103 1879
20 Massalia 8.3 2.409 0.142880 145 1852

* Apophis will only achieve that brightness on April 13, 2029.[8][9] It typically has an apparent magnitude of 20–22.

Exceptionally slowly rotating objects[edit]

Rotation periods have been determined for only a small fraction of asteroids (from light curves or from radar studies). Most asteroids have rotation periods of less than 24 hours. There are 17 objects with a likely rotation period greater than 30 days (720 hours). Asteroids larger than 150 meters usually have rotation periods longer than 2 hours.

Name Rotation
period
(hours)
(162058) 1997 AE12 1,880
846 Lipperta 1,641
912 Maritima 1,332
1235 Schorria 1,265
288 Glauke 1,200
4524 Barklajdetolli 1,069
1069 Planckia 1,060
(38063) 1999 FH 990
9556 Gaywray 920
9000 Hal 908
(391033) 2005 TR15 850
(22166) 2000 WX154 800
2862 Vavilov 800
1663 van den Bos 740
4902 Thessandrus 738
3322 Lidiya 710
(16896) 1998 DS9 708
1479 Inkeri 660
(7352) 1994 CO 648
(37635) 1993 UJ1 600
9165 Raup 560
27810 Daveturner 546
1042 Amazone 540
(188077) 2001 XW47 525
(96590) 1998 XB 520
(11351) 1997 TS25 515
6498 Ko 500
1220 Crocus 491.4
253 Mathilde 417.7
5851 Inagawa 367.5
79360 Sila–Nunam 300.24
2010 WG9 263.8
(369984) 1998 QR52 234
3691 Bede 226.8
9969 Braille 226.4
(38071) 1999 GU3 216
(65407) 2002 RP120 200

See also: Minor Planet Lightcurve Parameters

Fastest-rotating objects[edit]

Asteroids smaller than 150 meters usually have rotation periods shorter than 2 hours. With a rotation period of 3.74 hours, 201 Penelope is the fastest-rotating asteroid larger than 50 km in diameter.

Name Rotation
period
(seconds)
Diameter
(m)
2014 RC 15.8 22
2010 JL88 24.6 15
2010 WA 30.9 3
2008 HJ 42.7 24
2009 TM8 43.2 9
2010 SK13 51.8 14
2009 BF2 57.3 28
2000 DO8 78 30
2003 DW10 ~100 20
2003 EM1 111.6 33

Orbital characteristics[edit]

Retrograde[edit]

Minor planets with orbital inclinations greater than 90° (the greatest possible is 180°) orbit in a retrograde direction. As of July 2015, of the 688,321 minor planets known, there are only 65 known retrograde minor planets.[10] In comparison, there are over 1920 comets with retrograde orbits. This makes retrograde minor planets the rarest group of all. High-inclination asteroids are either Mars-crossers (possibly in the process of being ejected from the Solar System) or damocloids. Some of these are temporarily captured in retrograde resonance with the gas giants.[11]

Retrograde
Name Inclination Discovery date Condition code obs number
× obs arc[1]
Comment
2005 SB223 91.419° September 30, 2005 3 12200 Has a well-determined orbit with a data arc of 244 days (Uncertainty Parameter=1)
2014 MH55 91.49° June 29, 2014 9 96
2010 EQ169 91.606° March 8, 2010 9 32
2014 PP69 93.627° August 5, 2014 5 4816
2015 BH311 95.575° January 20, 2015 9 39
2014 JJ57 95.958° May 9, 2014 3 61802
2014 HS150 96.456° April 16, 2014 8 200
2013 BL76 98.607° January 20, 2013 1 46716 Has a semi-major axis of 1254 AU, giving it the third largest semi-major axis of any known minor planet
2010 GW147 99.623° April 14, 2010 3 93632
2011 MM4 100.446° June 24, 2011 4 36036
2014 XS3 100.934° December 8, 2014 9 55
2013 BN27 101.780° January 17, 2013 7 1425
2008 KV42 103.483° May 31, 2008 5 10449
(342842) 2008 YB3 105.031° December 18, 2008 1 864896
2010 GW64 105.273° April 6, 2010 4 9576
2012 YO6 106.914° December 22, 2012 4 6674
2009 DD47 107.431° February 27, 2009 7 1584
2007 VW266 108.345° November 12, 2007 7 2280
2015 MJ116 108.876° June 27, 2015 9
2011 SP25 108.987° September 20, 2011 5 3712
2011 OR17 110.345° May 21, 2010 1 75548
2005 TJ50 110.368° October 3, 2005 7 1488
2005 VX3 112.459° November 1, 2005 4 4050 Semi-major axis of 837AU, but has a somewhat short 81-day observation arc for such a large orbit
2010 OM1 118.689° July 28, 2010 5 3232
(65407) 2002 RP120 119.106° September 4, 2002 2 660275 This outer-planet crosser is a damocloid and SDO.
2010 PO58 121.229° August 5, 2010 9 168
2010 LG61 123.732° June 2, 2010 9 770
2015 KB157 124.316° May 28, 2015 9
2013 LU28 125.414° June 8, 2013 5 21560
2014 SQ339 128.499° September 9, 2014 7 1276
2000 DG8 129.478° February 25, 2000 3 44460 A damocloid and SDO. Crosses all the outer planets except Neptune. Came within 0.03 AU of Ceres in 1930.[12]
2013 NS11 130.340° July 5, 2013 2 71929
2005 NP82 130.549° July 6, 2005 6 8769
2007 VA85 131.879° November 4, 2007 5 18480 Near-Earth object that makes approaches to Jupiter and Earth.[13]
2006 RG1 133.195° September 1, 2006 6 750 Has an orbit with a data arc of 25 days (Uncertainty Parameter=4)
2012 YE8 136.136° December 21, 2012 7 1189
2009 QY6 137.654° August 17, 2009 4 43560
2015 AO44 139.949° November 27, 2014 4
(336756) 2010 NV1 140.818° July 2, 2010 1 266805 Perihelion at 9.4 AU, only 2008 KV42 has perihelion further out (154-day data arc)
2011 WS41 141.645° November 24, 2011 8 108
2010 OR1 143.861° January 25, 2010 4 35416
2010 BK118 143.910° January 30, 2010 1 385148 Semi-major axis of 408 AU with perihelion at 6.1 AU in April 2012 (1 year data arc)
2010 CG55 146.246° February 15, 2010 2 124816
2012 HD2 146.897° April 18, 2012 2 32314
2009 YS6 147.797° December 17, 2009 1 199547
2006 EX52 150.240° March 5, 2006 2 62930 q=2.58 AU and period=274 yr
1999 LE31 151.807° June 12, 1999 3 51943 A damocloid, Jupiter- and Saturn-crossing minor planet.[14]
(343158) 2009 HC82 154.496° April 29, 2009 0 385700 NEO that has the highest relative velocity to Earth (282,900 km/hr) of objects that come within 0.5 AU of Earth.
2013 LD16 154.748° June 6, 2013 3 14148
2015 FK37 155.985° March 20, 2015 5 748
2010 EB46 156.531° March 12, 2010 7 2610
2000 HE46 158.448° April 29, 2000 4 26400
2012 TL139 160.036° October 8, 2012 6 900
20461 Dioretsa 160.404° June 8, 1999 2 256779 most highly inclined known minor planet from 1999/06/08-2004/02/10
2015 BZ509 163.026° January 14, 2015 290
2006 RJ2 164.582° September 14, 2006 7 2812
2006 BZ8 165.315° January 23, 2006 2 214312  
2004 NN8 165.466° July 13, 2004 2 23944 Came within 0.80 AU of Saturn on 2007-Jun-05
2014 AT8 165.554° January 3, 2014 3 42517
(330759) 2008 SO218 170.318° September 30, 2008 1 733950
2014 UV114 170.510° October 26, 2014 9 34
2014 CW14 170.747° February 10, 2014 7 1938 most highly inclined known minor planet from 2004/02/10-2005/11/01
2006 LM1 172.138° June 3, 2006 9 48 Has a data arc of only 2 days (Uncertainty Parameter=E), but has a very high inclination
(434620) 2005 VD 172.866° November 1, 2005 2 130989 most highly inclined known minor planet from 2005/11/01-2013/06/01
2013 LA2 175.189° June 1, 2013 8 1075 Has the highest inclination of any known minor planet

^ the value given when the number of observations is multiplied by the observation arc; larger values are generally better than smaller values depending on residuals.

Highly inclined[edit]

High-inclination
Name Inclination Discovery date Comment
1 Ceres 10.593° January 1, 1801 most highly inclined known minor planet from 1801/01/01-1802/03/28
2 Pallas 34.841° March 28, 1802 most highly inclined known minor planet from 1802/03/28-1920/10/31
944 Hidalgo 42.525° October 31, 1920 most highly inclined known minor planet from 1920/10/31-1950/05/22
1373 Cincinnati 38.949° August 30, 1935 First main-belt asteroid discovered to have an inclination greater than 2 Pallas. Most highly inclined known main-belt asteroid from 1935/08/30-1980/06/14
1580 Betulia 52.083° May 22, 1950 most highly inclined known minor planet from 1950/05/22-1973/07/04
2938 Hopi 41.436° June 14, 1980 Most highly inclined known main-belt asteroid from 1980/06/14-2000/09/20
(5496) 1973 NA 67.999° July 4, 1973 A Mars-crosser and near-Earth object. most highly inclined known minor planet from 1973/07/04-1999/06/08
(22653) 1998 QW2 45.794° August 17, 1998 Most highly inclined known main-belt asteroid from 1998/08/17-1998/10/19
(88043) 2000 UE110 51.998° October 29, 2000 First main-belt asteroid discovered and numbered to have an inclination greater than 50°.
(138925) 2001 AU43 72.132° January 4, 2001 A Mars-crosser and near-Earth object.
(127546) 2002 XU93 77.904° December 4, 2002 A damocloid and SDO. It is almost a Uranus outer-grazer.
(196256) 2003 EH1 70.790° March 6, 2003 A Mars-crosser, near-Earth object and Jupiter inner-grazer.
1998 UQ1 64.281° October 19, 1998 Most highly inclined known main-belt asteroid from 1998/10/19-2007/11/01
2004 LG 70.725° June 9, 2004 A Mercury- through Mars-crosser and near-Earth object.
2007 VR6 68.659° November 1, 2007 Most highly inclined known main-belt asteroid from 2007/11/01-2008/09/26
2008 SB85 74.247° September 26, 2008 Most highly inclined known main-belt asteroid from 2008/09/26-2010/03/08(?)
2010 EQ169 91.606° March 8, 2010 Most highly inclined known main-belt asteroid(?) (orbit is not well-known)
2010 OA101 84.426° July 17, 2010 Outer main-belt asteroid with a semi-major axis of 4.5 AU (54-day data arc). Most highly inclined known main-belt asteroid(?) (assuming 2010 EQ169 has a lower inclination)

Trojans[edit]

Record-setting close approaches to Earth[edit]

Timeline[edit]

Landmark asteroids[edit]

Name Diameter (km) Discovered Comment
5 Astraea 117 December 8, 1845 First asteroid discovered after original four (38 years later)
87 Sylvia 261 May 16, 1866 First asteroid known to have more than one moon (determined in 2005)
90 Antiope 80×80 October 1, 1866 Double asteroid with two nearly equal components; its double nature was discovered using adaptive optics in 2000
92 Undina 126 1867 July 7 Created in one of the largest asteroid-on-asteroid collisions of the past 100 million years
216 Kleopatra 217×94 April 10, 1880 Metallic asteroid with "dog-bone" shape and 2 satellites
243 Ida 56×24×21 September 29, 1884 First asteroid known to have a moon (determined in 1993)
243 Ida I Dactyl 1.4 February 17, 1994 Moon of 243 Ida, first confirmed satellite of an asteroid
279 Thule 127 October 25, 1888 Orbits in the asteroid belt's outermost edge in a 3:4 orbital resonance with Jupiter
288 Glauke 32 February 20, 1890 Exceptionally slow rotation period of about 1200 hours (2 months)
323 Brucia 36 December 22, 1891 First asteroid discovered by means of astrophotography rather than visual observation
433 Eros 13×13×33 August 13, 1898 First near-Earth asteroid discovered and the second largest; first asteroid to be detected by radar
490 Veritas 115 September 3, 1902 Created in one of the largest asteroid-on-asteroid collisions of the past 100 million years
588 Achilles 135.5 February 22, 1906 First Jupiter trojan discovered
624 Hektor 370×195 February 10, 1907 Largest Jupiter trojan discovered
719 Albert 2.4 October 3, 1911 Last numbered asteroid to be lost then recovered
1125 China   October 30, 1957 First asteroid discovery to be credited to an institution rather than a person
1566 Icarus 1.4 June 27, 1949 First Mercury crosser discovered
1902 Shaposhnikov 97 April 18, 1972 The most recent main-belt asteroid discovered that is ~100+ km in diameter
2063 Bacchus 1.1×1.1×2.6 April 24, 1977  
3200 Phaethon 5 October 11, 1983 First asteroid discovered from space; source of Geminids meteor shower.
3753 Cruithne 5 October 10, 1986 Unusual Earth-associated orbit
4179 Toutatis 4.5×2.4×1.9 January 4, 1989 Closely approached Earth on September 29, 2004
4769 Castalia 1.8×0.8 August 9, 1989 First asteroid to be radar-imaged in sufficient detail for 3D modeling[15]
5261 Eureka ~2–4 June 20, 1990 First Mars trojan (Lagrangian point L5) discovered
11885 Summanus   September 25, 1990 First automated discovery of a near-Earth object (NEO)
(29075) 1950 DA 1.1 February 23, 1950 Will approach Earth very closely in 2880, collision possibility
69230 Hermes 0.3 October 28, 1937 Named but not numbered until its recovery in 2003 (65 years later)
99942 Apophis 0.3 June 19, 2004 First asteroid to rank greater than one on the Torino Scale (it was ranked at 2, then 4; now down to 0). Previously better known by its provisional designation 2004 MN4.
1997 XR2 0.23 December 4, 1997 First asteroid to rank greater than zero on the impact-risk Torino Scale (it was ranked 1; now at 0)
1998 KY26 0.030 June 2, 1998 Approached within 800,000 km of Earth
2002 AA29 0.1 January 9, 2002 Unusual Earth-associated orbit
2004 FH 0.030 March 15, 2004 Discovered before it approached within 43,000 km of Earth on March 18, 2004.
2008 TC3 ~0.003 October 6, 2008 First Earth-impactor to be spotted before impact (on October 7, 2008)
2010 TK7 ~0.3 October 2010 First Earth trojan to be discovered
2014 RC ~0.017 September 1, 2014 Asteroid with fastest rotation: 16.2 seconds

Spacecraft targets[edit]

Name Diameter
(km)
Discovered Spacecraft Year(s) Closest
approach
(km)
closest
approach
(asteroid radii)
Notes Landmark(s)
1 Ceres 952 January 1, 1801 Dawn 2014–present approx. 200 (planned) 0.42 Dawn took its first "close up" picture of Ceres in December 2014, and entered orbit in March 2015 First dwarf planet visited by a spacecraft, largest asteroid visited by a spacecraft
4 Vesta 529 March 29, 1807 Dawn 2011–2012 210 0.76 Dawn broke orbit on 5 September 2012 and headed to Ceres, where it arrived in March 2015 First "big four" asteroid visited by a spacecraft, largest asteroid visited by a spacecraft at the time
21 Lutetia 120×100×80 November 15, 1852 Rosetta 2010 3,162 64.9 Flyby on 10 July 2010 Largest asteroid visited by a spacecraft at the time
243 Ida 56×24×21 September 29, 1884 Galileo 1993 2,390 152 Flyby; discovered Dactyl First asteroid with a moon visited by a spacecraft, largest asteroid visited by spacecraft at the time
253 Mathilde 66×48×46 November 12, 1885 NEAR Shoemaker 1997 1,212 49.5 Flyby Largest asteroid visited by a spacecraft at the time
433 Eros 13×13×33 August 13, 1898 NEAR Shoemaker 1998–2001 0 0 1998 flyby; 2000 orbited (first asteroid studied from orbit); 2001 landing First asteroid landing, first asteroid orbited by a spacecraft, first near-Earth asteroid (NEA) visited by a spacecraft
951 Gaspra 18.2×10.5×8.9 July 30, 1916 Galileo 1991 1,600 262 Flyby first asteroid visited by a spacecraft
2867 Šteins 4.6 November 4, 1969 Rosetta 2008 800 302 Flyby First asteroid visited by the ESA
4179 Toutatis 4.5×~2 February 10, 1934 Chang'e 2 2012 3.2 0.70 Flyby[16] Closest asteroid flyby, first asteroid visited by China
5535 Annefrank 4.0 March 23, 1942 Stardust 2002 3,079 1230 Flyby
9969 Braille 2.2×0.6 May 27, 1992 Deep Space 1 1999 26 12.7 Flyby; followed by flyby of Comet Borrelly
25143 Itokawa 0.5×0.3×0.2 September 26, 1998 Hayabusa 2005 0 0 Landed; returned dust samples to Earth First asteroid with returned samples, smallest asteroid visited by a spacecraft, first asteroid visited by a non-NASA spacecraft

Numbered minor planets that are also comets[edit]

Name Cometary name Comment
2060 Chiron 95P/Chiron First centaur discovered in 1977, later identified to exhibit cometary behaviour. Also one of two minor planets known to have a ring system
4015 Wilson–Harrington 107P/Wilson–Harrington In 1992, it was realized that asteroid 1979 VA's orbit matched it with the positions of the lost comet Wilson–Harrington (1949 III)
7968 Elst–Pizarro 133P/Elst–Pizarro Discovered in 1996 as a comet, but orbitally matched to asteroid 1979 OW7
60558 Echeclus 174P/Echeclus Centaur discovered in 2000, comet designation assigned in 2006
118401 LINEAR 176P/LINEAR (LINEAR 52) Main-belt cometasteroid discovered to have a coma on November 26, 2005

Note there are quite a few other cases where a non-numbered asteroid with only a systematic designation (such as 2001 OG108) turned out to be a comet (in this case C/2001 OG108 (LONEOS)). The above table lists only numbered asteroids that are also comets.

Minor planets that were misnamed and renamed[edit]

In earlier times, before the modern numbering and naming rules were in effect, asteroids were sometimes given numbers and names before their orbits were precisely known. And in a few cases duplicate names were given to the same object (with modern use of computers to calculate and compare orbits with old recorded positions, this type of error no longer occurs). This led to a few cases where asteroids had to be renamed.[17]

330 Adalberta An object discovered March 18, 1892 by Max Wolf with provisional designation "1892 X" was named 330 Adalberta, but was lost and never recovered. In 1982 it was determined that the observations leading to the designation of 1892 X were stars, and the object never existed. The name and number 330 Adalberta was then reused for another asteroid discovered by Max Wolf on February 2, 1910, which had the provisional designation A910 CB.
525 Adelaide The object A904 EB discovered March 14, 1904 by Max Wolf was named 525 Adelaide and was subsequently lost. Later, the object 1930 TA discovered October 3, 1930 by Sylvain Arend was named 1171 Rusthawelia. In those pre-computer days, it was not realized until 1958 that these were one and the same object. The name Rusthawelia was kept (and discovery credited to Arend); the name 525 Adelaide was reused for the object 1908 EKa discovered October 21, 1908 by Joel Hastings Metcalf.
715 Transvaalia and 933 Susi The object 1911 LX discovered April 22, 1911 by H. E. Wood was named 715 Transvaalia. On April 23, 1920, the object 1920 GZ was discovered and named 933 Susi. In 1928 it was realized that these were one and the same object. The name Transvaalia was kept, and the name and number 933 Susi was reused for the object 1927 CH discovered February 10, 1927 by Karl Reinmuth.
864 Aase and 1078 Mentha The object A917 CB discovered February 13, 1917 by Max Wolf was named 864 Aase, and the object 1926 XB discovered December 7, 1926 by Karl Reinmuth was named 1078 Mentha. In 1958 it was discovered that these were one and the same object. In 1974, this was resolved by keeping the name 1078 Mentha and reusing the name and number 864 Aase for the object 1921 KE, discovered September 30, 1921 by Karl Reinmuth.
1095 Tulipa and 1449 Virtanen The object 1928 DC discovered February 24, 1928 by Karl Reinmuth was named 1095 Tulipa, and the object 1938 DO discovered February 20, 1938 by Yrjö Väisälä was named 1449 Virtanen. In 1966 it was discovered that these were one and the same object. The name 1449 Virtanen was kept and the name and number 1095 Tulipa was reused for the object 1926 GS discovered April 14, 1926 by Karl Reinmuth.
1125 China and 3789 Zhongguo The object 1928 UF discovered October 25, 1928 by Zhang Yuzhe (Y. C. Chang) was named 1125 China, and was later lost. Later, the object 1957 UN1 was discovered on October 30, 1957 at Purple Mountain Observatory and was initially incorrectly believed to be the rediscovery of the object 1928 UF. The name and number 1125 China were then reused for the object 1957 UN1, and 1928 UF remained lost. In 1986, the object 1986 QK1 was discovered and proved to be the real rediscovery of 1928 UF. This object was given the new number and name 3789 Zhongguo. Note Zhongguo is the Mandarin Chinese word for "China", in pinyin transliteration.
Asteroid 1317 The object 1914 UQ discovered April 20, 1914 by G. N. Neujmin was named 787 Moskva (and retains that name to this day). The object 1934 FD discovered on March 19, 1934 by C. Jackson was given the sequence number 1317. In 1938, G. N. Neujmin found that asteroid 1317 and 787 Moskva were one and the same object. The sequence number 1317 was later reused for the object 1935 RC discovered on September 1, 1935 by Karl Reinmuth; that object is now known as 1317 Silvretta.

See also[edit]

Books[edit]

  • Dictionary of Minor Planet Names, 5th ed.: Prepared on Behalf of Commission 20 Under the Auspices of the International Astronomical Union, Lutz D. Schmadel, ISBN 3-540-00238-3

References[edit]

  1. ^ Savage, Don; Jones, Tammy; Villard, Ray (1995). "Asteroid or Mini-Planet? Hubble Maps the Ancient Surface of Vesta". Hubble Site News Release STScI-1995-20. Retrieved 2006-10-17. 
  2. ^ "JPL Small-Body Database Search Engine: asteroids and orbital class (IMB or MBA or OMB) and diameter > 120 (km)". JPL's Solar System Dynamics Group. Retrieved 2012-04-16. 
  3. ^ a b "Recent Asteroid Mass Determinations". Maintained by Jim Baer. Last updated 2010-12-12. Access date 2011-09-02.
  4. ^ Baer, James; Steven R. Chesley (2008). "Astrometric masses of 21 asteroids, and an integrated asteroid ephemeris" (PDF). Celestial Mechanics and Dynamical Astronomy (Springer Science+Business Media B.V. 2007) 100 (2008): 27–42. Bibcode:2008CeMDA.100...27B. doi:10.1007/s10569-007-9103-8. Retrieved 2008-11-11. 
  5. ^ Pitjeva, E. V. (2004). "Estimations of masses of the largest asteroids and the main asteroid belt from ranging to planets, Mars orbiters and landers". 35th COSPAR Scientific Assembly. Held 18–25 July 2004, in Paris, France. p. 2014. Bibcode:2004cosp.meet.2014P. 
  6. ^ Michalak, G. (2001). "Determination of asteroid masses". Astronomy & Astrophysics 374 (2): 703–711. Bibcode:2001A&A...374..703M. doi:10.1051/0004-6361:20010731. Retrieved 2008-11-10. 
  7. ^ Michalak, G. (2001), assumed masses of perturbing asteroids used in calculations of perturbations of the test asteroids.
  8. ^ "(99942) Apophis Ephemerides for 13 Apr 2029". NEODyS (Near Earth Objects - Dynamic Site). Retrieved 2011-05-05. 
  9. ^ "(99942) Apophis Ephemerides for 13 Apr 2029". Minor Planet Center Ephemeris Service - Dynamic Site). 
  10. ^ "JPL Small-Body Database Search Engine: Asteroids and i > 90 (deg)". JPL Solar System Dynamics. Retrieved 2015-01-31. 
  11. ^ Morais, M.H.M.; F. Namouni. "Asteroids in retrograde resonance with Jupiter and Saturn". Monthly Notices of the Royal Astronomical Society Letters (in press). arXiv:1308.0216. 
  12. ^ 2008 DG8 and Ceres in 1930
  13. ^ 2007 VA85 and Jupiter/Earth
  14. ^ 1999 LE31 approaches to Jupiter and Saturn
  15. ^ "1994 Release #9412" (Press release). NASA. 1994-02-18. Retrieved 2008-04-17. 
  16. ^ Chang'E 2 images of Toutatis – December 13, 2012 – The Planetary Society
  17. ^ http://pdssbn.astro.umd.edu/SBNast/archive/DISCOVER/discnote.tab

External links[edit]