Minor-planet moon

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243 Ida and its moon Dactyl as imaged by the Galileo spacecraft in 1993
762 Pulcova and satellite as seen with adaptive optics in 2000

A minor-planet moon is an astronomical body that orbits a minor planet as its natural satellite. It is thought that many asteroids and Kuiper belt objects may possess moons, in some cases quite substantial in size. Discoveries of minor-planet moons (and binary objects, in general) are important because the determination of their orbits provides estimates on the mass and density of the primary, allowing insights of their physical properties that is generally not otherwise possible.[1] As of November 2011, there are over 200 minor planets known to have moons.[2]

Terminology[edit]

In addition to the terms satellite and moon, the term binary is sometimes used for minor planets with moons (or triple for minor planets with two moons). If one object is much bigger it can be referred to as the primary and its companion as secondary. The term double asteroid is sometimes used for systems in which the asteroid and its moon are roughly the same size, while binary tends to be used independently from the relative sizes of the components. When binary minor planets are similar in size, the Minor Planet Center (MPC) refers to them as "binary companions" instead of referring to the smaller body as a satellite.[3] A good example of a true binary is the 90 Antiope system, identified in August 2000.[4] Small satellites are often referred to as moonlets.[1][5]

Discovery milestones[edit]

As of June 2013, over 230 moons of minor planets have been discovered.[2] These consist of:

Prior to the era of the Hubble telescope and space probes reaching the outer Solar System, attempts to detect satellites around asteroids were limited to optical observations from Earth. For example, in 1978, stellar occultation observations were claimed as evidence of a satellite for the asteroid 532 Herculina.[7] However, later more-detailed imaging by the Hubble Telescope did not reveal a satellite, and the current consensus is that Herculina does not have a significant satellite.[8] There were other similar reports of asteroids having companions (usually referred to as satellites) in the following years. Also, a letter in Sky & Telescope magazine[citation needed] at this time pointed to apparently simultaneous impact craters on Earth (for example, the Clearwater Lakes in Quebec), suggesting that these craters were caused by pairs of gravitationally-bound objects.

In 1993, the first asteroid moon was confirmed when the Galileo probe discovered the small Dactyl orbiting 243 Ida in the asteroid belt. The second was discovered around 45 Eugenia in 1998.[9] In 2001, 617 Patroclus and its same-sized companion Menoetius became the first known binary asteroids in the Jupiter Trojans.[10] The first trans-Neptunian binary, 1998 WW31, was optically resolved in 2002.[11]

Triple systems[edit]

In 2005, the asteroid 87 Sylvia was discovered to have two satellites, making it the first known triple asteroid.[12] This was followed by the discovery of a second moon orbiting 45 Eugenia.[13] Also in 2005, the Kuiper belt object (KBO) Haumea was discovered to have two moons, making it the second KBO after Pluto known to have more than one moon. Other known triple systems include: 3749 Balam (March 2008),[14] 216 Kleopatra (September 2008),[15] and 93 Minerva (August 2009).[16]

Commonality[edit]

The data about the populations of binary objects are still patchy. In addition to the inevitable observational bias (dependence on the distance from Earth, size, albedo and separation of the components) the frequency appears to be different among different categories of objects. Among asteroids, an estimated 2% would have satellites. Among trans-Neptunian objects (TNO), an estimated 11% are believed to be binary or multiple objects, but three of the four known large TNO (75%) have at least one satellite.

More than 20 binaries are known in each of the main groupings: near-Earth asteroids, main-belt asteroids, and trans-Neptunians, not including numerous claims based solely on light-curve variation.

No binaries have been found so far among centaurs with semi-major axis smaller than Neptune.[17] However, using an extended definition of Centaurs, as the objects on unstable orbits with the perihelion inside the orbit of Neptune, the first binary centaur, 42355 Typhon (previously known as 2002 CR46), was identified in 2006.[18]

Origin[edit]

The origin of minor-planet moons is not currently known with certainty, and a variety of theories exist. A widely accepted theory is that minor-planet moons are formed from debris knocked off of the primary by an impact. Other pairings may be formed when a small object is captured by the gravity of a larger one.

Formation by collision is constrained by the angular momentum of components i.e. by the masses and their separation. Close binaries fit this model (e.g. PlutoCharon). Distant binaries however, with components of comparable size, are unlikely to have followed this scenario, unless considerable mass has been lost in the event.

The distances of the components for the known binaries vary from a few hundreds of kilometres (243 Ida, 3749 Balam) to more than 3000 km (379 Huenna) for the asteroids. Among TNOs, the known separations vary from 3,000 to 50,000 km.[17]

Populations[edit]

What is "typical" for a binary system tends to depend on its location in the Solar System (presumably because of different modes of origin and lifetimes of such systems in different populations of minor planets).[19]

  • Among near-Earth asteroids, satellites tend to orbit at distances of the order of 3–7 primary radii, and have diameters two to several times smaller than the primary. Since these binaries are all inner-planet crossers, it is thought that tidal stresses that occurred when the parent object passed close to a planet may be responsible for the formation of many of them, although collisions are thought to also be a factor in the creation of these satellites.
  • Among main-belt asteroids, the satellites are usually much smaller than the primary (a notable exception being 90 Antiope), and orbit around 10 primary radii away. Many of the binary systems here are members of asteroid families, and a good proportion of satellites are expected to be fragments of a parent body whose disruption after an asteroid collision produced both the primary and satellite.
  • Among trans-Neptunian objects, it is common for the two orbiting components to be of comparable size, and for the semi-major axis of their orbits to be much larger − about 100 to 1000 primary radii. A significant proportion of these binaries are expected to be primordial.

Dwarf planets[edit]

Among the dwarf planets, it is 90 percent certain that Ceres has no moons larger than 1 km in size, assuming that they would have the same albedo as Ceres itself.[20]

Pluto has five known moons. Its largest moon Charon is more than half the size of Pluto itself, and large enough to orbit a point outside Pluto's surface. In effect, each orbits the other, forming a binary system informally referred to as a double dwarf planet. Pluto's four other moons, Nix, Hydra, Kerberos, and Styx, are far smaller and orbit the Pluto–Charon system.

Haumea has two moons with radii estimated around 155 km (Hiʻiaka) and 85 km (Namaka).

Makemake has no known moons. A satellite having 1% Makemake's brightness would have been detected if it had been located at an angular distance from Makemake farther than 0.4 arcseconds (0.0001 degrees; 2 microradians).[21]

Eris has one known moon, Dysnomia. Its radius, based on its brightness, is estimated to be roughly between 150 and 350 km.[22]

List of minor planets with moons[edit]

Near-Earth objects[edit]

Radar images of asteroid (66391) 1999 KW4 and its moon. The 'streaks' on the image are the moon's trail as it moved while the images were created.
Near-Earth encounter of asteroid (136617) 1994 CC in June 2009, showing two moons
Name Type Diameter (km)
(or dimensions)
Name of moon Diameter of moon (km)
(or dimensions)
Separation (km)
1862 Apollo Apollo 1.7 S/2005 (1862) 1 0.08 3
3671 Dionysus Amor 1.5 S/1997 (3671) 1 0.4 2.2
5381 Sekhmet Aten 1 S/2003 (5381) 1 0.3 1.54 ± 0.12
7088 Ishtar Amor 1.5? S/2006 (7088) 1  ?  ?
(31345) 1998 PG Amor 0.9 S/2001 (31345) 1 0.3 1.5
(35107) 1991 VH Apollo 1.2 S/2001 (35107) 1 0.5 3.2
65803 Didymos Amor 0.8 S/2003 (65803) 1 0.15 ± 0.05 1.1
(66063) 1998 RO1 Aten 0.9 S/2001 (66063) 1 0.36 0.8
(66391) 1999 KW4 Aten 1.2 S/2001 (66391) 1 0.45 ± 0.03 2.6
69230 Hermes Apollo 0.4 S/2003 (69230) 1 0.4 1
(85938) 1999 DJ4 Apollo 0.7 S/2004 (85938) 1 0.35 1.5
(88710) 2001 SL9 Apollo 1 S/2001 (88710) 1 0.31 1.8
(153591) 2001 SN263 Amor 2.6 2 moons: Gamma (inner), Beta (outer)  ? 3.8, 16.6
(136617) 1994 CC Apollo 0.7 2 moons: Beta (inner), Gamma (outer)  ? 1.7, 6.1
(137170) 1999 HF1 Aten 3.5 S/1999 (137170) 1 0.8 7.0
(162000) 1990 OS Apollo 0.3 S/2003 (1990 OS) 1 0.045 0.6
(164121) 2003 YT1 Apollo 1 S/2004 (2003 YT1) 1 0.18 ~2.7
(175706) 1996 FG3 Apollo 1.4 S/2001 (1996 FG3) 1 0.43 2.4
(185851) 2000 DP107 Apollo 0.80 (± 0.16) S/2000 (2000 DP107) 1 0.30 (± 0.15) 2.622 ± 0.162
(285263) 1998 QE2 Amor 2.75 S/2013 (285263) 1 0.6  ?
1994 AW1 Amor 0.9 S/2001 (1994 AW1) 1 0.5 2.1
1994 XD Apollo 1? S/2005 (1994 XD) 1  ?  ?
1998 ST27 Aten 0.8 S/2002 (1998 ST27) 1 0.12 4.5 ± 0.5
2000 UG11 Apollo 0.23 ± 0.06 S/2001 (2000 UG11) 1 0.10 0.337 ± 0.013
2002 BM26 Amor 0.6 S/2002 (2002 BM26) 1 0.1 1.5
2002 CE26 Apollo 3 S/2004 (2002 CE26) 1 0.2 5
2002 KK8 Amor 0.5 S/2003 (2002 KK8) 1 0.1  ?
2003 SS84 Apollo 0.12 S/2004 (2003 SS84) 1 0.06 0.3?
2004 DC Apollo 0.3 S/2006 (2004 DC) 1  ?  ?
2005 AB Amor 1.2? S/2005 (2005 AB) 1 0.3 2.5?
2005 NB7 Apollo 0.5 ± 0.1 S/2008 (2005 NB7) 1 0.2 ± 0.1 ≥ 0.6
2006 GY2 Apollo 0.45 S/2006 (2006 GY2) 1  ?  ?

Mars crossers[edit]

Name Diameter (km)
(or dimensions)
Name of moon Diameter of moon (km)
(or dimensions)
Separation (km)
1139 Atami 7 S/2005 (1139) 1 5 15?
2044 Wirt 7 S/2006 (2044) 1 2  ?
(5407) 1992 AX 4 S/2001 (5407) 1 1.2 6.8
(34706) 2001 OP83 4? S/2005 (34706) 1 1? 8?
(114319) 2002 XD58 3? S/2005 (114319) 1  ?  ?

Main-belt asteroids[edit]

Name Diameter (km)
(or dimensions)
Name of moon Diameter of moon (km)
(or dimensions)
Separation (km)
22 Kalliope (215×180×150) Linus 38 ± 6 1,065 ± 8
41 Daphne (239x183x153) S/2008 (41) 1 <2 443
45 Eugenia (305×220×145) Petit-Prince (Eugenia I) 13 ± 1 1,184 ± 12
S/2004 (45) 1 ~6 ~700(?)
87 Sylvia (385×265×230) Remus (Sylvia II) 7 ± 2 706 ± 5
Romulus (Sylvia I) 18 ± 4 1,356 ± 5
90 Antiope 110±16 S/2000 (90) 1 110 ± 16 170 ± 1
93 Minerva 140 Aegis (Minerva I) 4 630?
Gorgoneion (Minerva II) 3 380?
107 Camilla (285×205×170) ± 20 S/2001 (107) 1 11 ± 2 1,235 ± 16
121 Hermione (254×125) S/2002 (121) 1 12 ± 4 768 ± 11
130 Elektra (215×155) S/2003 (130) 1 6 ± 2 1,252 ± 30
216 Kleopatra 217×94×81 Alexhelios (Kleopatra I) 5 650
Cleoselene (Kleopatra II) 3 380
243 Ida (59.8×25.4×18.6) Dactyl (Ida I) (1.6×1.4×1.2) 108
283 Emma 148.1 ± 4.6 S/2003 (283) 1 12 596 ± 3
379 Huenna 92.3 ± 1.7 S/2003 (379) 1 7 3,400 ± 11
702 Alauda 194.73 ± 3.2 S/2007 (702) 1 5.5 900
762 Pulcova 137.1 ± 3.2 S/2000 (762) 1 20 810
809 Lundia ~7–10 S/2005 (809) 1 ~7–10 ~10–20
854 Frostia 13.7 ± 5.6 S/2004 (854) 1 10 ~25
1089 Tama 12.9 S/2003 (1089) 1 9 20
1313 Berna 11 S/2004 (1313) 1 11 35
1338 Duponta 8–19 S/2007 (1338) 1 ~3?  ?
1509 Esclangona 12 S/2003 (1509) 1 4 140
1717 Arlon 9? S/2006 (1717) 1  ? 18?
2006 Polonskaya 10 S/2005 (2006) 1  ?  ?
2478 Tokai 10? S/2007 (2478) 1 7?  ?
2486 Metsähovi[23] 12? S/2007 (2486) 1  ?  ?
2754 Efimov 7? S/2006 (2754) 1  ? 12?
3073 Kursk 8? S/2007 (3073) 1  ?  ?
3309 Brorfelde 6? S/2005 (3309) 1  ?  ?
3703 Volkonskaya 3 S/2003 (3703) 1 1.2  ?
3749 Balam 7 S/2002 (3749) 1 1.5 310 ± 20
S/2008 (3749) 1 3 ~20
3782 Celle 6 S/2003 (3782) 1 2.5 30
3982 Kastel  ? S/2005 (3982) 1  ?  ?
4029 Bridges 10 S/2006 (4029) 1  ?  ?
4492 Debussy 10 S/2004 (4492) 1  ? 25
4674 Pauling 8 S/2004 (4674) 1 2.5 250
4786 Tatianina 8? S/2006 (4786) 1  ?  ?
5477 Holmes ~7 S/2005 (5477) 1 2.5 15
5905 Johnson 5 S/2005 (5905) 1 2  ?
6084 Bascom 9? S/2006 (6084) 1 3.5? 32?
6244 Okamoto 7? S/2006 (6244) 1 1.7? 15?
9069 Hovland 3 S/2004 (9069) 1 0.9  ?
9260 Edwardolson ~4 S/2005 (9260) 1  ?  ?
9617 Grahamchapman 5? S/2006 (9617) 1 1.4?  ?
11264 Claudiomaccone 4 S/2003 (11264) 1 1.2  ?
(17246) 2000 GL74 4.5 S/2004 (17246) 1 2 ~230
(17260) 2000 JQ58 6? S/2006 (17260) 1 1.5? 10?
(22899) 1999 TO14 4.5 S/2003 (22899) 1 1.5 ~170
(76818) 2000 RG79 3.6 S/2005 (76818) 1 1.1  ?

Jupiter trojans[edit]

Name Diameter (km)
(or dimensions)
Name of moon Diameter of moon (km)
(or dimensions)
Separation (km)
617 Patroclus 121.8 ± 3.2 Menoetius (Patroclus I) 112.6 ± 3.2 685 ± 40
624 Hektor (363×207) S/2006 (624) 1 15 1,000?

Trans-Neptunian objects[edit]

Name Type Diameter (km)
(or dimensions)
Name of moon Diameter of moon (km)
(or dimensions)
Separation (km)
134340 Pluto Plutino 2306 ± 20 Charon (Pluto I) 1207 ± 3 19,571 ± 4
Styx (Pluto V) 10-25 42,000 ± 2000
Nix (Pluto II) 46-137 48,675 ± 120
Kerberos (Pluto IV) 13–34 59,000 ± 2,000
Hydra (Pluto III) 61-167 64,780 ± 90
(26308) 1998 SM165 Plutino 221? S/2001 (26308) 1 88 11,310 ± 110
42355 Typhon SDO 134 Echidna (Typhon I) 78 1,300?
(47171) 1999 TC36 Plutino A1=286 +45
−38

A2=265 +41
−35
S/2001 (47171) 1 139 +22
−18
7411 ± 12
(48639) 1995 TL8 SDO 352 S/2002 (48639) 1 161 420
50000 Quaoar Cubewano <1100 Weywot (Quaoar I) 96?  ?
(55637) 2002 UX25 Cubewano 649 S/2007 (55637) 1 205  ?
58534 Logos Cubewano 80 Zoe (Logos I) 66 8,010 ± 80
(60458) 2000 CM114 SDO 150? S/2006 (60458) 1 119? 2,200?
(60621) 2000 FE8 2:5 resonance 151? S/2007 (60621) 1 115? 1,200
65489 Ceto SDO 172 Phorcys (Ceto I) 134 1,840
66652 Borasisi Cubewano 166 Pabu (Borasisi I) 137 4,660 ± 170
79360 Sila–Nunam Cubewano 305 S/2005 (79360) 1 292 2300
(80806) 2000 CM105 Cubewano 224 S/2005 (80806) 1 129 2700
(82075) 2000 YW134 SDO 431 S/2005 (82075) 1 237 1900
88611 Teharonhiawako Cubewano 176 ± 20 Sawiskera (Teharonhiawako I) 122 ± 14 27,300 ± 343
90482 Orcus Plutino 946 Vanth (Orcus I) 262 ± 170 8,700
(119979) 2002 WC19 1:2 resonance 420? S/2007 (119979) 1  ?  ?
120347 Salacia Cubewano 580? Actaea (Salacia I) 190? 3,500?
(123509) 2000 WK183 Cubewano 221? S/2007 (123509) 1  ?  ?
(134860) 2000 OJ67 Cubewano 253? S/2003 (134860) 1 175? 2,300?
136108 Haumea Cubewano 1400 Hiʻiaka (Haumea I) 310 49,500 ± 400
Namaka (Haumea II) 170 39,300
136199 Eris SDO 2326 Dysnomia (Eris I) 150–250 30,000–36,000
(139775) 2001 QG298 Plutino 171? S/2004 (139775) 1 171? 240?
148780 Altjira Cubewano 340? S/2007 (148780) 1 246? 5,800?
174567 Varda cubewano 690? Ilmarë (Varda I) 350? 4,200
(182933) 2002 GZ31 SDO 187? S/2007 (2002 GZ31) 1 118? ~2,060 ± 270
(208996) 2003 AZ84 Plutino 686 +99
−96
S/2007 (2003 AZ84) 1 68 ± 20 7,200
385446 Manwë 4:7 resonance ≈140 Thorondor (Manwë I) ≈70 6674 ± 41
1998 WW31 Cubewano 133 ± 15 S/2000 (1998 WW31) 1 110 ± 12 22,300 ± 800
1999 OJ4 Cubewano? 168 S/2005 (1999 OJ4) 1 93 2,200
1999 RT214 Cubewano 120? S/2006 (1999 RT214) 1  ? 3,300?
2000 CF105 Cubewano 170 S/2001 (2000 CF105) 1 120 23,000
2000 CQ114 Cubewano 164? S/2004 (2000 CQ114) 1 133 5,880 ± 200
2000 QL251 Cubewano? 176? S/2006 (2000 QL251) 1 176? 7,000?
2001 FL185 Cubewano 144? S/2007 (2001 FL185) 1 100? 1,900?
2001 QY297 Cubewano 282? S/2007 (2001 QY297) 1 233? 2,800?
2001 RZ143 Cubewano 201? S/2007 (2001 RZ143) 1 192? 1,400?
2001 QC298 Cubewano 189 S/2002 (2001 QC298) 1 155 3,690 ± 70
2001 QW322 Cubewano 86 S/2003 (2001 QW322) 1 86 ~130,000
2003 QW111 Plutino 265? S/2006 (2003 QW111) 1  ? 10,000?
2003 QY90 SDO 196 S/2003 (2003 QY90) 1 178 10,000
2003 UN284 Cubewano 127 S/2003 (2003 UN284) 1 97 60,000
2004 PB108 Cubewano 210? S/2007 (2004 PB108) 1 121? 5,400
2005 EO304 Cubewano 240 S/2005 (2005 EO304) 1  ? 85,000

See also[edit]

References[edit]

  1. ^ a b Dr. William J. Merline and Maria Martinez (2000-10-26). "Astronomers Image Double Asteroid". SwRI Press Release. Retrieved 2009-10-20.  (mentions both 90 Antiope and 762 Pulcova)
  2. ^ a b c Wm. Robert Johnston (2009-10-16). "Asteroids with Satellites". Johnston's Archive. Retrieved 2009-10-20. 
  3. ^ "Satellites and Companions of Minor Planets". IAU / Minor Planet Center. 2009-09-17. Retrieved 2011-01-08. 
  4. ^ "90 Antiope: Raw Keck Image". SWrI Press Release. August 2000. Retrieved 2009-10-20. 
  5. ^ "IAUC 8732: S/2006 (624) 1". Retrieved 2011-01-08.  (Satellite Discovery)
  6. ^ Marchis, F.; Baek, M.,; Berthier, J.; Descamps, P.; Emery, J.P.; Macomber, B.; Pollock, J.; Vachier, F. (2008). "Multiple Asteroid Systems: New Techniques to Study New Worlds". Lunar and Planetary Institute. Retrieved 2009-10-20. 
  7. ^ Satellite of Minor Planet 532 Herculina Discovered During Occultation. David W. Dunham, The Minor Planet Bulletin, Volume 6, p.13–14 (December 1978) ADS archive copy
  8. ^ Storrs, Alex Weiss; Zellner; Burleson; Sichitiu; Wells; Kowal; Tholen (1999). "Imaging observations of asteroids with Hubble Space Telescope". Icarus 137 (2): 260–268. Bibcode:1999Icar..137..260S. doi:10.1006/icar.1999.6047. 
  9. ^ "Astronomers Discover Moon Orbiting Asteroid". SwRI. 1998. Retrieved 2009-10-21.  (Eugenia AO image)
  10. ^ Merline, W. J. (2001). "IAUC 7741: 2001fc; S/2001 (617) 1; C/2001 T1, C/2001 T2". 
  11. ^ Chiang, E.; Lithwick, Y.; Buie, M.; Grundy, W.; Holman, M.; A Brief History of Trans-Neptunian Space, to appear in Protostars and Planets V (August 2006) Final preprint on arXiv
  12. ^ Daniel W. E. Green (2005-08-11). "IAUC 8582: Sats OF (87)". International Astronomical Union Circular. Retrieved 2011-01-08. 
  13. ^ Daniel W. E. Green (2007-03-07). "IAUC 8817: S/2004 (45) 1". International Astronomical Union Circular. Retrieved 2011-01-08. 
  14. ^ Franck Marchis (Principal Investigator, SETI Institute, UC Berkeley). "Franck Marchis Web Page". Department of Astronomy (University of California at Berkeley). Retrieved 2009-10-27. 
  15. ^ Franck Marchis (Principal Investigator, SETI Institute, UC Berkeley) (2008-09-19). "Two Companions Found Near Dog-Bone Asteroid". SETI Institute. Retrieved 2009-10-26. 
  16. ^ Franck Marchis (2009-08-21). "The discovery of a new triple asteroid – (93) Minerva". Cosmic Diary Blog. Retrieved 2009-10-27. 
  17. ^ a b Noll, Keith S. "Solar System binaries", Asteroids, Comets, Meteors, Proceedings of the 229th Symposium of the IAU, Rio de Janeiro, 2005, Cambridge University Press, 2006., pp. 301–318 Preprint
  18. ^ K. Noll, H. Levison W. Grundy, D. Stephens (October 2006). "Discovery of a binary Centaur". Icarus 184. 
  19. ^ "T. Michałowski et al. (2004). "Eclipsing binary asteroid 90 Antiope". Astronomy & Astrophysics 423 (3): 1159. Bibcode:2004A&A...423.1159M. doi:10.1051/0004-6361:20040449. 
  20. ^ Bieryla, Allyson; Parker, J. W. (December 2006). "Search for Satellites around Ceres". 2007 AAS/AAPT Joint Meeting, American Astronomical Society Meeting 209, #25.02; Bulletin of the American Astronomical Society 38: 933. Bibcode:2006AAS...209.2502B. 
  21. ^ Brown, M. E.; Van Dam, M. A.; Bouchez, A. H.; Le Mignant, D.; Campbell, R. D.; Chin, J. C. Y.; Conrad, A.; Hartman, S. K.; Johansson, E. M.; Lafon, R. E.; Rabinowitz, D. L. Rabinowitz; Stomski, P. J., Jr.; Summers, D. M.; Trujillo, C. A.; Wizinowich, P. L. (2006). "Satellites of the Largest Kuiper Belt Objects" (PDF). The Astrophysical Journal 639 (1): L43–L46. arXiv:astro-ph/0510029. Bibcode:2006ApJ...639L..43B. doi:10.1086/501524. Retrieved 2011-10-19.  edit
  22. ^ Santos-Sanz, P.; et al. (2012). ""TNOs are Cool": A Survey of the Transneptunian Region IV. Size/albedo characterization of 15 scattered disk and detached objects observed with Herschel Space Observatory-PACS". arXiv:1202.1481 [astro-ph.EP].
  23. ^ http://www.cbat.eps.harvard.edu/cbet/000800/CBET000860.txt CBET 860
  • Asteroids with Satellites web page, maintained up to date by W. Robert Johnston; and references therein. (last accessed 13-03-2007)
  • The VOBAD database a web page built and designed by F. Marchis and his collaborators (UC-Berkeley/SETI Institute) which contains the parameters of 169 multiple asteroid systems (last update May 9, 2009)

External links[edit]