| Discovery[1] | |
|---|---|
| Discovered by | R. M. West |
| Discovery site | La Silla Obs. |
| Discovery date | 24 October 1976 |
| Designations | |
| (2187) La Silla | |
Named after | La Silla Observatory (observatory and mountain)[2] |
| 1976 UH | |
| main-belt · Eunomia[3] | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 40.42 yr (14,764 days) |
| Aphelion | 2.8354AU |
| Perihelion | 2.2352 AU |
| 2.5353 AU | |
| Eccentricity | 0.1184 |
| 4.04yr (1,474 days) | |
| 139.36° | |
| 0° 14m 39.12s / day | |
| Inclination | 13.261° |
| 137.27° | |
| 214.21° | |
| Physical characteristics | |
| Dimensions | 6.64 km(calculated)[3] 12.320±0.093 km[4][5] 12.96±0.70 km[6] |
| 11.8431±0.0049 h[7] 16h[8] | |
| 0.054±0.004[4][5] 0.080±0.010[6] 0.21(assumed)[3] | |
| S[3] | |
| 13.00[4][6] · 13.2[1][3] · 13.21±0.38[9] · 13.307±0.005(R)[7] | |
2187 La Silla, provisionally designated1976 UH, is a stony Eunomiaasteroid from the middle region of theasteroid belt, approximately 12 kilometers in diameter.
It was discovered on 24 October 1976 by Danish astronomerRichard Martin West atESO'sLa Silla site in northern Chile, and named after the discovering observatory and the mountain it is located on.[2][10]
La Silla is a member of theEunomia family, a large collisional group ofS-type asteroids and the most prominent family in the intermediate main-belt. It orbits the Sun in thecentral main-belt at a distance of 2.2–2.8 AU once every 4.04 years (1,474 days). Its orbit has aneccentricity of 0.12 and aninclination of 13° with respect to theecliptic.[1]La Silla'sobservation arc begins with its discovery observation in 1976, as noprecoveries were taken, and no previous identifications were made.[10]
In July 2007, French amateur astronomerRené Roy obtained a rotationallightcurve from photometric observations, giving arotation period of 16 hours with a brightness variation of 0.6magnitude (U=2-).[8] In March 2010, photometric observations at thePalomar Transient Factory gave a shorter period of 11.843 hours with an amplitude of 0.35 magnitude (U=2).[7]
According to the space-based survey carried out by the JapaneseAkari satellite and NASA'sWide-field Infrared Survey Explorer with its subsequentNEOWISE mission,La Silla measures 12.32 and 12.96 kilometers in diameter, and its surface has analbedo of 0.054 and 0.08, respectively.[4][5][6] TheCollaborative Asteroid Lightcurve Link assumes an albedo of 0.21 – derived from15 Eunomia, the family's largest member and namesake – and calculates a diameter of 6.64 kilometers.[3]
Thisminor planet is named after the site whereESO's discoveringLa Silla Observatory is situated. La Silla is a 2400-metre mountain on the outskirts of theAtacama Desert, north of the city ofLa Serena in northern Chile.[2][11] The official naming citation was published by theMinor Planet Center on 1 December 1979 (M.P.C. 5039).[12]
