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Asteroid is a 
minor planet
According to the International Astronomical Union (IAU), a minor planet is an astronomical object in direct orbit around the Sun that is exclusively classified as neither a planet nor a comet. Before 2006, the IAU officially used the term ''minor ...
from the outer Solar System and the first known Uranus trojan There are two known Uranus trojans, or minor planets orbiting in the Lagrangian points of Uranus. Both are in the region:
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See also
* Trojan (astronomy)
In astronomy, a trojan is a small celestial body (mostly asteroids) that shares the ...
to be discovered. It measures approximately in diameter, assuming an albedo of 0.05. 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.
temporarily orbits near Uranus's Lagrangian point
In celestial mechanics, the Lagrange points (; also Lagrangian points or libration points) are points of equilibrium for small-mass objects under the influence of two massive orbiting bodies. Mathematically, this involves the solution of th ...
(leading Uranus). It will continue to librate around for at least 70,000 years and will remain a Uranus co-orbital
In astronomy, a co-orbital configuration is a configuration of two or more astronomical objects (such as asteroids, moons, or planets) orbiting at the same, or very similar, distance from their primary, i.e. they are in a 1:1 mean-motion resonan ...
for up to three million years. is thus a temporary Uranus trojan—a centaur captured some time ago.
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 orbit
In celestial mechanics, a horseshoe orbit is a type of co-orbital configuration, co-orbital motion of a small orbiting body relative to a larger orbiting body. The osculating orbit, osculating (instantaneous) orbital period of the smaller body re ...
s, 10% (0.04%) would be quasi-satellites, and 26% (0.104%) would be trojans (evenly split between the and groups). A second Uranian Trojan, , was announced in 2017.
References
External links
* {{DEFAULTSORT:2011 QF99 Trojan minor planets Uranus co-orbital minor planets Minor planet object articles (unnumbered) 20110829