2011 QF99
| Discovery | |
|---|---|
| Discovery date | 2011[1] |
| Designations | |
| Minor planet category | centaur |
| Orbital characteristics[2] | |
| Epoch JD 2456400.5 (18 April 2013) | |
| Aphelion | 22.547 AU |
| Perihelion | 15.775 AU |
| Semi-major axis | 19.090 AU |
| Eccentricity | 0.1765 |
| Orbital period | 83.87 yr (30,635 d) |
| Mean anomaly | 266.88° |
| Inclination | 10.81° |
| Longitude of ascending node | 222.49° |
| Argument of perihelion | 287.51° |
| Physical characteristics | |
| Dimensions | ~60 km[2] |
| Albedo | 0.05 (assumed) |
| Absolute magnitude (H) |
9.6 (r-band)[2] 9.7[1] |
|
| |
2011 QF99 is the first and as of 2013 the only Uranus trojan identified.[2][3] It was discovered in 2011 during a deep survey of trans-Neptunian objects conducted with the Canada–France–Hawaii Telescope.[2][4] It is believed to be roughly 60 km in diameter, assuming an albedo of 0.05.[2]
2011 QF99 temporarily orbits near Uranus's L4 Langrangian point (leading Uranus). It will continue to librate around L4 for at least 70,000 years and will remain a Uranus co-orbital for up to three million years before becoming a centaur. 2011 QF99 is thus a temporary Uranus trojan—a centaur captured some time ago.[2]
Uranus trojans are generally expected to be unstable and none of them are thought to be of primordial origin. A simulation study concluded that at any given time, 0.4% of the centaurs in the scattered population within 34 AU would be Uranus co-orbitals; of these, it was predicted that 64% would be in horseshoe orbits, 10% would be quasi-satellites, and 26% would be trojans (evenly split between the L4 and L5 groups).[2]
References
- ↑ 1.0 1.1 "JPL Small-Body Database Browser: 2011 QF99". Retrieved 2013-03-29.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 Alexandersen, M.; Gladman, B.; Greenstreet, S.; Kavelaars, J. J.; Petit, J. -M.; Gwyn, S. (2013). "A Uranian Trojan and the Frequency of Temporary Giant-Planet Co-Orbitals". Science 341 (6149): 994–997. arXiv:1303.5774. doi:10.1126/science.1238072. PMID 23990557.
- ↑ Choi, C. Q. (2013-08-29). "First 'Trojan' Asteroid Companion of Uranus Found". Space.com web site. TechMediaNetwork. Retrieved 2013-09-03.
- ↑ Alexandersen, M.; Kavelaars, J.; Petit, J.; Gladman, B. (18 March 2013). MPEC 2013-F19: 2011 QF99. IAU. Retrieved 3 September 2013.
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