Contact binary asteroids, TNOs, and comets

Contact Binary Asteroids, TNOs, and Comets
compiled by Wm. Robert Johnston
last updated 15 April 2023

Of those asteroids for which shapes have been determined, a number have bilobated or contact binary shapes. These objects likely relate to true binary asteroids (i.e. with physically separated components) in origin.

The following table lists known and suspected contact binary solar system objects: 83 asteroids, 14 trans-Neptunian objects, and 7 comets. "Method" column indicates method used to determine shape; "morphology" column indicates shapes other than strict contact binary. Sources regarding shape are listed below the table, along with other sources (e.g., for rotation periods).

This table does not include a number of asteroids that are known or believed to be genuine binaries, with two distinct components, but with very small separations. These include: near-Earth asteroids (5143) Heracles, (363027) 2000 CO101, (374851) 2006 VV2, and (488453) 1994 XD; main belt asteroid (11264) Claudiomaccone; Jupiter trojans (17365) 1978 VF11 and (29314) Eurydamas; and trans-Neptunian object (139775) 2001 QG298.

asteroid
92	Undina
110	Lydia
121	Hermione
129	Antigone
201	Penelope
216	Kleopatra
413	Edburga
624	Hektor
678	Fredegundis
758	Mancunia
779	Nina
1981	Midas
2063	Bacchus
3169	Ostro
3752	Camillo
4179	Toutatis
4450	Pan
4486	Mithra
4769	Castalia
5836
8567
11066	Sigurd
13553	Masaakikoyama
25143	Itokawa
47932
52387	Huitzi
68346
85989
85990
90403
96590
99942	Apophis
126719
137126
141593
143404
144411
152664
153201
163696
179806
192642
231937
242191
242643
275677
348306
367789
385446	Manwe
388188
398188	Agni
413260
418135
436774
438661
443880
462959
481394
481817
486958	Arrokoth
494999
496817
503941
511684
523804
524594
525268
531074
532039
533562
554292
578992
609221
612342
612620
612813
612891
612929




















1P	Halley
8P	Tuttle
19P	Borrelly
45P		67P	Churyu
103P	Hartley 2
331P-A	Gibbs 14

rowspan=2>dynamical
typedimensions (km)rotation
period (h)methodmorphologyyear
reportedsource des.ABC main belt asteroid 126 15.941 radar 2010S15a main belt asteroid 86 10.927 radar 2008S15a main belt asteroid 250 120 120 5.55128AO imagery 2005M05a main belt asteroid 113 4.9572 radar/lightcurve 2010S15a main belt asteroid 105 72 62 3.7474 radar/lightcurve 2015S15a main belt asteroid 217 94 81 5.385 radar "dog bone" 2000O00a 1896 CL main belt asteroid 46 29 25 15.773 radar/lightcurve 2015S15a 1907 XM Jupiter trojan 363 207 207 6.924 lightcurve 1978H78a 1909 FS main belt asteroid 40 11.61624radar 2008S08a 1912 PE main belt asteroid 90 12.7253 radar 2006S10a 1914 UB main belt asteroid 81 11.186 radar 2008S15a 1973 EA Apollo asteroid 3.4 1.9 1.3 5.222 radar bilobated 2018B18a, B21a, M22a 1977 HB Apollo asteroid 1.11 0.53 0.50 14.904 radar 1998B99a 1981 LA main belt asteroid 4.6 1.7 1.6 6.503 lightcurve 2007D07a 1985 PA Apollo asteroid 2.3 37.846 radar 2018B18a 1989 AC Apollo asteroid 4.6 2.29 1.92 176 radar bilobated 1992H95a 1987 SY Apollo asteroid 1 56.48 radar 2008B16a 1987 SB Apollo asteroid 2.35 1.65 1.44 67.5 radar 2000B10a 1989 PB Apollo asteroid 1.7 1 1 4.095 radar 1990O90a 1993 MF Amor asteroid 4.9543 lightcurve 2017B17a 1996 HW1 Amor asteroid 3.78 1.64 1.49 8.76243radar 2011M11b 1992 CC1 Apollo asteroid 4.2 ~2 ~2 8.4958 radar 2004B12a 1992 JE Amor asteroid ~2 0.8 58 radar 2022V22a 1998 SF36 Apollo asteroid 0.535 0.294 0.209 12.132 SC imagery bilobated 2005D06a 2000 GN171 TNO/Plutino 147 8.329 lightcurve 2017S02a lopochtli1993 OM7 Amor asteroid 1.22 >26 radar 2003B16a 2001 KZ66 Apollo asteroid 1.51 0.64 0.78 4.98599radar 2003B16a, Z21a 1999 JD6 Aten asteroid 1.8 7.6638 radar "peanut" 2014W14a 1999 JV6 Apollo asteroid 0.73 0.37 0.35 6.53678radar bilobated 2016B16a, R19a 2003 YE45 Apollo asteroid 1 0.5 0.5 505 radar bilobated 2022V22a 1998 XB Aten asteroid 0.9 520 radar 2017B17a 2004 MN4 Aten asteroid 0.43 0.30 0.26 30.56 radar 2015B15b 2002 CC249 TNO ~210 11.87 lightcurve 2017T17a 1999 CF9 Apollo asteroid 0.9 6.7 radar 2013B15a 2002 HK12 Apollo asteroid 0.6 12.69 radar 2002B15a 2003 BD44 Apollo asteroid 78.64 radar 2017B17a 2004 EW9 Apollo asteroid 2 1 1 49.94 radar 2012B16a 1998 FW4 Apollo asteroid 0.3 17.38 radar 2009B16a 2000 WO107Aten asteroid 0.82 0.38 5.022 radar 2020B20a 2003 EB50 Apollo asteroid 62.06 radar "peanut" 2015B16a 2002 TD66 Apollo asteroid 0.3 9.455 radar 2008B16a 1999 RD32 Apollo asteroid 6 17.08 radar 2012B16a 2001 FO32 Apollo asteroid 1.2 ~0.5 ~0.5 39.905 radar "peanut" 2021B21a 2003 NZ6 Aten asteroid 0.6 0.3 0.3 13.531 radar 2015B16a 2005 NZ6 Apollo asteroid 1.99 >10 radar 2013B15a 2000 RS11 Apollo asteroid 0.698 0.578 0.758 4.444 radar 2014B15a 2005 AY28 Aten asteroid 0.2 6.292 radar 2014B15a 2011 AG5 Apollo asteroid 0.5 0.15 9.44 radar bilobed 2022B23a, N23a 2003 QW111 TNO/resonant 142 11.8819 lightcurve 2017T19a 2006 DP14 Apollo asteroid 0.4 0.2 0.2 5.77 radar 2014J14a 2010 LE15 Aten asteroid 0.44 21.99 radar 2015B15a 2003 TL4 Aten asteroid 0.4 27.2 radar 2017B17a 2008 AG33 Apollo asteroid 0.33 radar 2022B22a 2012 KY3 Apollo asteroid ~0.4 ~0.25 radar 2023B23b 2008 EP6 Apollo asteroid 0.4 5 radar 2016B16a 2001 UZ16 Apollo asteroid 0.4 13.719 radar 2016B16a 2011 DU Apollo asteroid 0.2 10.290 radar 2017B17a 2006 SF6 Aten asteroid 0.32 0.12 11.4876 radar 2020Z20a, V22a 2008 UL90 Atira asteroid ~0.6 radar 2017B17a 2014 MU69 TNO/cubewano 35 20 10 15.918 occultation, imagingbilobed and lenticular2017S19a 2010 JU39 Aten asteroid >0.16 ~0.1 30.2 radar 2022V22a 1989 VB Apollo asteroid 0.4 14.533 radar 2017B17a 2003 UV11 Apollo asteroid 0.4 18.25 radar 2010B16a 2015 BN509 Apollo asteroid 0.3 5.6713 radar 2017B17a 2000 YF29 Apollo asteroid 0.4 <12 radar 2001B12a 2003 NW1 Apollo asteroid 0.7 0.35 37.7 radar 2022V22a 2004 XL14 Aten asteroid 0.3 24 radar 2006B12a 2012 DX98 TNO/resonant ~150 20.8 lightcurve 2019T19a, T22a 2013 FR28 TNO/resonant ~150 lightcurve 2019T19a 2014 JQ80 TNO/Plutino ~165 ~83 ~63 12.16 lightcurve 2018T18a 2012 TC24 Jupiter trojan ~7 lightcurve 2018D18a 2014 JL80 TNO/Plutino ~170 34.87 lightcurve 2018T18a 2004 VC131 TNO/cubewano ~260 15.7 lightcurve 2019T19a 2002 FC Apollo asteroid 0.7 >40 radar 2002B15a 2003 SQ317 TNO/Haumea family ~380 ~190 ~180 7.210 lightcurve 2017L13a 2004 RF84 Apollo asteroid 2.4 >300 radar 2005B15a 2004 TT357 TNO/2:5 resonance ~140 ~70 ~50 7.79 lightcurve 2017T17b 2005 CR37 Apollo asteroid 1.8 0.8 0.8 5.6 radar 2006B06a 2002 AY1 Aten asteroid ~0.2 8 radar 2013B15a 2002 NY40 Apollo asteroid 0.4 19.98 radar 2002T12a 2004 MU8 TNO/cubewano ~280 >2 lightcurve 2019T19a 2004 VU75 TNO/cubewano ~200 >3 lightcurve 2019T19a 2007 TU24 Apollo asteroid 0.3 26 radar 2008B16a 2007 VD12 Apollo asteroid 0.5 7.418 radar 2007B16a 2008 SV11 Apollo asteroid 0.8 32.4 radar 2009B16a 2009 DL46 Apollo asteroid 0.1 42.26 radar 2017B17a 2010 GT7 Apollo asteroid 0.32 0.22 ~16 radar 2022V22a 2012 MS4 Apollo asteroid 0.48 0.25 <42 radar 2022V22a 2012 QG42 Apollo asteroid 0.25 24.22 radar 2013B16a 2013 JB36 Amor asteroid ~0.25 radar 2013H13a 2013 JR28 Apollo asteroid 0.1 >10 radar 2013B15a 2014 HQ124Aten asteroid 0.325 20 radar 2014B15a 2014 JO25 Apollo asteroid 0.87 0.65 4.5 radar 2017N17b 2014 JO80 TNO/Plutino ~113 ~66 ~47 6.32 lightcurve 2018T18a 2014 UF206Amor asteroid 1 6.83 radar 2015B15a 2015 JD1 Apollo asteroid 0.15 0.1 0.1 5.2116 radar 2020L20a, L22a 2017 BW Apollo asteroid 0.05 14.559 radar 2017B17a 2021 LD1 Apollo asteroid 1.2 radar 2021B21b P/1682 Q1 Halley family comet 15.1 8.0 7.7 54 SC imagery "peanut" 1986S91a P/1858 A1 Jupiter family comet 10 5.75 4.11 11.385 radar 2010H10a P/1904 Y2 Jupiter family comet 4.4 1.8 26 SC imagery 2002S04a nowrap>Honda-Mrkos-PajdusakovaP/1948 X1Jupiter family comet 1.3 7.6 radar 2017U17a mov-GerasimenkoP/1969 R1 Jupiter family comet 4.1 4.1 3.3 12.4043 SC imagery "rubber ducky"2014S15b P/1986 E2 Jupiter family comet 2.3 ~0.8 18.236 SC imagery bi-lobed 2011H11a, T13a P/2012 F5-A comet/active asteroid 0.8 3.26 lightcurve symmetric 2021J21a

Sources:

B99a: Benner, L. A. M., et al., 1999, Radar observations of asteroid 2063 Bacchus, Icarus, 139:309-327.
B06a: Benner, L. A. M., et al., 2006, Near-Earth asteroid 2005 CR37: Radar images and photometry of a candidate contact binary, Icarus, 182:474-481.
B10a: Brozovic, M., et al., 2010, Radar observations and a physical model of contact binary asteroid 4486 Mithra, Icarus, 208:207-220.
B12a: Busch, M. W., et al., 2012, Radar imaging of 11066 Sigurd, 2000 YF29, and 2004 XL14 and the obliquity distribution of contact binary near-Earth asteroids, DPS#44, 302.05.
B15a: Benner, L., 2015, Binary and ternary near-Earth asteroids, JPL, on line [http://echo.jpl.nasa.gov/~lance/binary.neas.html].
B15b: Brozovic, M., et al., 2015, Size estimate of (99942) Apophis based on radar imaging, DPS meeting #47, 402.06.
B16a: Benner, L., 2016, Binary and ternary near-Earth asteroids, JPL, on line [http://echo.jpl.nasa.gov/~lance/binary.neas.html].
B17a: Benner, L., 2017, Binary and ternary near-Earth asteroids, JPL, on line [http://echo.jpl.nasa.gov/~lance/binary.neas.html].
B18a: Benner, L., 2018, Binary and ternary near-Earth asteroids, JPL, on line [http://echo.jpl.nasa.gov/~lance/binary.neas.html].
B20d: Benner, L. A. M., et al., 2020, Goldstone radar observations planning: (7753) 1988 XB, 2017 WJ16, and 2000 WO107, JPL, on line. link.
B21a: Benner, L. A. M., et al., 2021, Goldstone radar observations planning: (231937) 2001 FO32, JPL, on line [https://echo.jpl.nasa.gov/asteroids/2001FO32/2001FO32.2021.goldstone.planning.html].
B21b: Benner, L. A. M., et al., 2021, Goldstone radar observations planning: 2021 LD1, JPL, on line [https://echo.jpl.nasa.gov/asteroids/2021LD1/2021LD1.goldstone.planning.html].
B22a: Benner, L. A. M., et al., 2022, Goldstone radar observations planning: (418135) 2008 AG33, JPL, on line [https://echo.jpl.nasa.gov/asteroids/2008AG33/2008AG33.2022.planning.html].
B23a: Benner, L. A. M., et al., 2023, Goldstone radar observations planning: (367789) 2011 AG5, 2023 BU, 2023 BN6, and (199145) 2005 YY128, JPL, on line [https://echo.jpl.nasa.gov/asteroids/2011AG5/2011AG5.2023.goldstone.planning.html].
B23b: Benner, L. A. M., et al., 2023, Goldstone radar observations planning: 2012 KY3 and 2023 FM, JPL, on line [https://echo.jpl.nasa.gov/asteroids/2012KY3/2012KY3.2023.goldstone.planning.html].
D06a: Demura, H., et al., 2006, Pole and global shape of 25143 Itokawa, Science, 312:1347-1349.
D07a: Descamps, P., et al., 2007, Nature of the small main belt asteroid 3169 Ostro, Icarus, 189:362-369.
D18a: Deen, S., 2018, 2012 TC24 possibly elongated object/contact binary, Yahoo! Groups--MPML, on line [https://groups.yahoo.com/neo/groups/mpml/conversations/messages/33626].
H78a: Hartmann, W. K., and D. P. Cruikshank, 1978, The nature of Trojan asteroid 624 Hektor, Icarus, 36:353-366.
H95a: Hudson, R. S., and S. J. Ostro, 1995, Shape and non-principal axis spin state of asteroid 4179 Toutatis, Science, 270:84-86.
H10a: Harmon, J. K., M. C. Nolan, J. D. Giorgini, and E. S. Howell, 2010, Radar observations of 8P/Tuttle: A contact-binary comet, Icarus, 207:499-502.
H11a: Harmon, J. K., M. C. Nolan, E. S. Howell, J. D. Giorgini, and P. A. Taylor, 2011, Comet 103P/Hartley: Radar observations of the nucleus and large-grain coma, 42nd LPSC, 1480.
H13a: Howell, E. S., M. C. Nolan, and P. A. Taylor, 2013, Radar characterization of NEAs: Using moderate resolution imaging astrometry, and a systematic survey [http://www.naic.edu/~pradar/curentNEO_2.pdf].
J14a: JPL, 2014, Radar images of near-Earth asteroid 2006 DP14, JPL, on line [http://www.jpl.nasa.gov/news/news.php?release=2014-060].
J21a: Jewitt, D., J. Li, and Y. Kim, 2021, Fragmenting active asteroid 331P/Gibbs, Astronomical Journal, 162(6):268.
L13a: Lacerda, P., A. McNeill, and N. Peixinho, 2013, The unusual Kuiper belt object 2003 SQ317, MNRAS, 437(4):3824-3831.
L20a: Lopez-Oquendo, A., et al., 2020, Optical, infrared, and radar observations of 2015 JD1: Evidence of surface inhomogeneity, BAAS, 52(6):2020n6i415p01.
L22a: Lopez-Oquendo, A., et al., 2022, Physical characterization of 2015 JD1: A possibly inhomogeneous near-Earth asteroid, submitted to Planetary Science Journal; arXiv, [https://arxiv.org/abs/2207.05208].
M05a: Marchis, F., D. Hestroffer, P. Descamps, J. Berthier, C. Laver, and I. de Pater, 2005, Mass and density of asteroid 121 Hermione from an analysis of its companion orbit, Icarus, 178:450-464.
M11b: Magri, C., et al., 2011, Radar and photometric observations and shape modeling of contact binary near-Earth asteroid (8567) 1996 HW1, Icarus, 214:210-227.
M21a: Marshall, S., et al., 2021, Shape models of near-Earth asteroids from Arecibo and Goldstone radar data, BAAS, 53(7):2021n7i306p12.
M22a: McGlasson, R. A., et al., 2022, Radar and lightcurve observations and a physical model of potentially hazardous asteroid 1981 Midas, Planetary Science Journal, 3:35.
N17a: NASA, 2017, New Horizons' next target just got a lot more interesting, NASA, on line [https://www.nasa.gov/feature/new-horizons-next-target-just-got-a-lot-more-interesting].
N17b: Naidu, S., et al., 2017, Goldstone radar imaging of near-Earth asteroids (469896) 2007 WV4, 2014 JO25, 2017 BQ6, and 2017 CS, AGU Fall Meeting 2017, #P33G-04.
N23a: NASA, 2023, PIA25259: Radar observations of elongated near-Earth asteroid 2011 AG5, NASA, on line [https://photojournal.jpl.nasa.gov/catalog/PIA25259].
O90a: Ostro, S. J., et al., 1990, Radar images of asteroid 1989 PB, Science, 248:1523-1528.
O00a: Ostro, S. J., et al., 2000, Radar observations of asteroid 216 Kleopatra, Science, 288:836-839.
R19a: Rozek, A., et al., 2019, Shape model and spin-state analysis of PHA contact binary (85990) 1999 JV6 from combined radar and optical observations, Astron. Astrophys., 631:A149.
S91a: Stooke, P. J., and A. Abergel, 1991, Morphology of the nucleus of comet P/Halley, Astron. & Astrophys., 248:656-668.
S02a: Sheppard, S. S., and D. C. Jewitt, Time-resolved photometry of Kuiper belt objects: Rotations, shapes, and phase functions, Astron. J., 124:1757-1775.
S04a: Soderblom, L. A., et al., 2004, Imaging Borrelly, Icarus, 167:4-15.
S08a: Stephens, R. D., B. D. Warner, M. K. Shepard, and A. W. Harris, 2008, Lightcurve and radar observations and analysis of 11 Parthenope and 678 Fredegundis, BAAS, 40:439.
S10a: Shepard, M. K., et al., 2010, A radar survey of M- and X-class asteroids. II. Summary and synthesis, Icarus, 208(1):221-237.
S15a: Shepard, M. K., et al., 2015, A radar survey of M- and X-class asteroids. III. Insights into their composition, hydration state, and structure, Icarus, 245:38-55.
S15b: Sierks, H., et al., 2015, On the nucleus structure and activity of comet 67P/Churyumov-Gerasimenko, Science, 347(6220).
S19a: Stern, S. A., et al., 2019, Initial results from the New Horizons exploration of 2014 MU69, a small Kuiper Belt object, Science, 364:649.
T12a: Taylor, P. A., et al., 2012, The Shape and Spin Distributions of Near-Earth Asteroids Observed with the Arecibo Radar System, Asteroids, Comets, Meteors 2012, LPI 1667:6340.
T13a: Thomas, P. C., et al., 2013, Shape, density, and geology of the nucleus of Comet 103P/Hartley 2, Icarus, 222(2):550-558.
T17a: Thirouin, A., and S. S. Sheppard, 2017, A possible dynamically cold classical contact binary: (126719) 2002 CC249, Astron. J., 154(6):241.
T17b: Thirouin, A., S. S. Sheppard, and K. S. Noll, 2017, 2004 TT357: A potential contact binary in the trans-Neptunian belt, Astrophys. J., 844(2):135.
T18a: Thirouin, A., and S. S. Sheppard, 2018, The plutino population: An abundance of contact binaries, Astron. J., forthcoming; arXiv [https://arxiv.org/abs/1804.09695].
T19a: Thirouin, A., and S. S. Sheppard, 2019, Colors of trans-Neptunian contact binaries.
T22a: Thirouin, A., and S. S. Sheppard, 2022, Lightcurves and rotations of trans-Neptunian objects in the 2:1 mean motion resonance with Neptune, Planetary Science Journal, forthcoming; arXiv [https://arxiv.org/abs/2206.09949].
U17a: USRA, 2017, Arecibo Observatory captures revealing images of Comet 45P/Honda-Mrkos-Pajdusakova, USRA, on line [http://www.usra.edu/news/pr/2017/comet45P/].
V22a: Virkki, A. K., et al., 2022, Arecibo planetary radar observations of near-Earth asteroids: 2017 December-2019 December, Planetary Science Journal, 3:222.
W14a: Warner, B. D., 2014, Near-Earth asteroid lightcurve analysis at CS3-Palmer Divide Station: 2014 March-June, Minor Planet Bulletin, 41:214-224.
W17a: Warner, B. D., 2017, Preliminary pole and shape models for three near-Earth asteroids, Minor Planet Bulletin, 44(3):206-212.
Z20a: Zambrano-Marin, L., et al., 2020, Arecibo science highlights of observatory planetary radar observations: 2019-2020, EPSC 2020, 992.
Z21a: Zegmott, T. J., et al., 2021, Detection of the YORP effect on the contact binary (68346) 2001 KZ66 from combined radar and optical observations, Monthly Notices of the Royal Astronomical Society, 507(4):4914-4932.

General sources:

Binary and ternary near-Earth asteroids (JPL)
Asteroid radar history (JPL)
JPL Small-body database (JPL)
Asteroid radar detections (UCLA)
NEODys-2 (ESA/UNIPI)
Warner, B. D., A. W. Harris, and P. Pravec, June 2021, Asteroid Lightcurve Data Base, on line [http://www.minorplanet.info/lightcurvedatabase.html].

© 2002-2022, 2023 by Wm. Robert Johnston.
Last modified 15 April 2023.
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