(687170) 2011 QF99

(687170) 2011 QF99
Animation of 2011 QF99 relative to Sun and Uranus 1600-2500
  2011 QF99 ·    Uranus  ·   Sun
Discovery
Discovered byM. Alexandersen[1]
Discovery siteMauna Kea Obs.
Discovery date29 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 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
60 km (calculated)[3]
0.05 (assumed)[3]
9.6 (R-band)[3]
9.7[2]

(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]

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]

  1. ^ a b Cite error: The named reference MPC-object was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference jpldata was invoked but never defined (see the help page).
  3. ^ a b c d e f g h Cite error: The named reference AlexandersenGladman2013 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference Choi_2013 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference MPEC2011 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference othersource was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference second was invoked but never defined (see the help page).