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]
Discovery | |
---|---|
Discovery site | Mauna Kea Obs. |
Discovery date | 29 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 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 | |
Mean diameter | 60 km (calculated)[2] |
0.05 (assumed)[2] | |
9.6 (R-band)[2] 9.7[1] | |
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]
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