2011 QF99
Discovery
Discovery siteMauna Kea Obs.
Discovery date29 August 2011[1]
(first observation only)
Designations
2011 QF99
Uranus trojan[2]
centaur[1] · distant[3]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 3
Observation arc3.97 yr (1,449 days)
Aphelion22.422 AU
Perihelion15.659 AU
19.040 AU
Eccentricity0.1776
83.08 yr (30,346 days)
283.84°
0° 0m 42.84s / day
Inclination10.833°
222.52°
288.25°
Physical characteristics
Mean diameter
60 km (calculated)[2]
0.05 (assumed)[2]
9.6 (R-band)[2]
9.7[1]

    Asteroid 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.[2][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.[2][5]

    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.[2][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).[2] A second Uranian Trojan, 2014 YX49, was announced in 2017.[7]

    Animation of 2011 QF99 relative to Sun and Uranus 1600-2500
      2011 QF99 ·    Uranus  ·   Sun

    References

    1. 1 2 3 4 "JPL Small-Body Database Browser: (2011 QF99)" (2012-10-21 last obs.). Jet Propulsion Laboratory. Retrieved 12 October 2017.
    2. 1 2 3 4 5 6 7 8 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.
    3. ↑ "2011 QF99". Minor Planet Center. Retrieved 12 October 2017.
    4. ↑ Choi, C. Q. (29 August 2013). "First 'Trojan' Asteroid Companion of Uranus Found". Space.com web site. TechMediaNetwork. Retrieved 3 September 2013.
    5. ↑ Alexandersen, M.; Kavelaars, J.; Petit, J.; Gladman, B. (18 March 2013). "MPEC 2013-F19: 2011 QF99". IAU. Retrieved 3 September 2013. {{cite journal}}: Cite journal requires |journal= (help)
    6. ↑ 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.
    7. ↑ 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.
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