(687170) 2011 QF99 is a minor planet from the outer Solar System and the first known Uranus trojan to be discovered. It measures approximately 60 kilometers (37 miles) in diameter, assuming an albedo of 0.05.[3][4] It was first observed 29 August 2011 during a deep survey of trans-Neptunian objects conducted with the Canada–France–Hawaii Telescope, but its identification as Uranian trojan was not announced until 2013.[3][5]
 Animation of 2011 QF99 relative to Sun and Uranus 1600-2500 2011 QF99 · Uranus · Sun | |
| Discovery | |
|---|---|
| Discovered by | M. Alexandersen[1] |
| Discovery site | Mauna Kea Obs. |
| Discovery date | 29 August 2011[2] (first observation only) |
| Designations | |
| 2011 QF99 | |
| Uranus trojan[3] centaur[2] · distant[1] | |
| Orbital characteristics[2] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 3 | |
| Observation arc | 3.97 yr (1,449 days) |
| Aphelion | 22.422 AU |
| Perihelion | 15.659 AU |
| 19.040 AU | |
| Eccentricity | 0.1776 |
| 83.08 yr (30,346 days) | |
| 283.84° | |
| 0° 0m 42.84s / day | |
| Inclination | 10.833° |
| 222.52° | |
| 288.25° | |
| Physical characteristics | |
| 60 km (calculated)[3] | |
| 0.05 (assumed)[3] | |
| 9.6 (R-band)[3] 9.7[2] | |
2011 QF99 temporarily orbits near Uranus's L4 Lagrangian 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. 2011 QF99 is thus a temporary Uranus trojan—a centaur captured some time ago.[3][6]
Uranus trojans are generally expected to be unstable and none of them are thought to be of primordial origin. A simulation led to the conclusion that at any given time, 0.4% of the centaurs in the scattered population within 34 AU would be Uranus co-orbitals, of which 64% (0.256% of all centaurs) would be in horseshoe orbits, 10% (0.04%) would be quasi-satellites, and 26% (0.104%) would be trojans (evenly split between the L4 and L5 groups).[3] A second Uranian Trojan, 2014 YX49, was announced in 2017.[7]
References
edit- ^ a b "2011 QF99". Minor Planet Center. Retrieved 12 October 2017.
- ^ a b c d "JPL Small-Body Database Browser: (2011 QF99)" (2012-10-21 last obs.). Jet Propulsion Laboratory. Retrieved 12 October 2017.
- ^ a b c d e f g h 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. Bibcode:2013Sci...341..994A. doi:10.1126/science.1238072. PMID 23990557. S2CID 39044607.
- ^ Choi, C. Q. (29 August 2013). "First 'Trojan' Asteroid Companion of Uranus Found". Space.com web site. TechMediaNetwork. Retrieved 3 September 2013.
- ^ Alexandersen, M.; Kavelaars, J.; Petit, J.; Gladman, B. (18 March 2013). "MPEC 2013-F19: 2011 QF99". Minor Planet Electronic Circulars. 2013-F19. IAU. Bibcode:2013MPEC....F...19A. Retrieved 3 September 2013.
- ^ de la Fuente Marcos, Carlos; de la Fuente Marcos, Raúl (22 May 2014). "Comparative orbital evolution of transient Uranian co-orbitals: exploring the role of ephemeral multibody mean motion resonances". Monthly Notices of the Royal Astronomical Society. 441 (3): 2280–2295. arXiv:1404.2898. Bibcode:2014MNRAS.441.2280D. doi:10.1093/mnras/stu733.
- ^ de la Fuente Marcos, Carlos; de la Fuente Marcos, Raúl (15 May 2017). "Asteroid 2014 YX49: a large transient Trojan of Uranus". Monthly Notices of the Royal Astronomical Society. 467 (2): 1561–1568. arXiv:1701.05541. Bibcode:2017MNRAS.467.1561D. doi:10.1093/mnras/stx197.
