Discovered by R. M. West MPC designation 2187 La Silla Minor planet category main-belt · Eunomia Orbits Sun Asteroid family Eunomia family Asteroid group Asteroid belt | Discovery date 24 October 1976 Alternative names 1976 UH Discovered 24 October 1976 Discoverer Richard Martin West Discovery site La Silla Observatory | |
Named after La Silla Observatory
(location of discovery) Similar Sun, Comet West, 85 Io, 812 Adele, 258 Tyche | ||
2187 La Silla, provisionally designated 1976 UH, is a stony Eunomia asteroid from the middle region of the asteroid belt, approximately 12 kilometers in diameter. It was discovered on 24 October 1976, by Danish astronomer Richard Martin West at ESO's La Silla site in northern Chile.
La Silla is a member of the Eunomia family, a large collisional group of S-type asteroids and the most prominent family in the intermediate main-belt. It orbits the Sun at a distance of 2.2–2.8 AU once every 4.04 years (1,475 days). Its orbit has an eccentricity of 0.12 and an inclination of 13° with respect to the ecliptic. La Silla's observation arc begins with its discovery observation in 1976, as no precoveries were taken, and no previous identifications were made.
In July 2007, French amateur astronomer René Roy obtained a rotational light-curve from photometric observations, giving a rotation period of 16 hours with a brightness variation of 0.6 magnitude (U=2-). In March 2010, photometric observations at the Palomar Transient Factory gave a shorter period of 11.843 hours with an amplitude of 0.35 magnitude (U=2).
According to the space-based survey carried out by the Japanese Akari satellite and NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, La Silla measures 12.32 and 12.96 kilometers in diameter, and its surface has an albedo of 0.054 and 0.08, respectively. The Collaborative Asteroid Lightcurve Link assumes an albedo of 0.21 – derived from 15 Eunomia, the family's largest member and namesake – and calculates a diameter of 6.64 kilometers.
This minor planet is named after the mountain in the Chilean Atacama desert on top of which ESO's discovering La Silla Observatory is situated. Naming citation was published on 1 December 1979 (M.P.C. 5039).