Astronomy:2187 La Silla
| 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 | |
| Minor planet category | 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) |
| |{{{apsis}}}|helion}} | 2.8354 AU |
| |{{{apsis}}}|helion}} | 2.2352 AU |
| 2.5353 AU | |
| Eccentricity | 0.1184 |
| Orbital period | 4.04 yr (1,474 days) |
| Mean anomaly | 139.36° |
| Mean motion | 0° 14m 39.12s / day |
| Inclination | 13.261° |
| Longitude of ascending node | 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] |
| Rotation period | 11.8431±0.0049 h[7] 16 h[8] |
| Geometric albedo | 0.054±0.004[4][5] 0.080±0.010[6] 0.21 (assumed)[3] |
| S [3] | |
| Absolute magnitude (H) | 13.00[4][6] · 13.2[1][3] · 13.21±0.38[9] · 13.307±0.005 (R)[7] |
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, and named after the discovering observatory and the mountain it is located on.[2][10]
Classification and orbit
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 in the central main-belt at a distance of 2.2–2.8 AU once every 4.04 years (1,474 days). Its orbit has an eccentricity of 0.12 and an inclination of 13° with respect to the ecliptic.[1] La Silla's observation arc begins with its discovery observation in 1976, as no precoveries were taken, and no previous identifications were made.[10]
Physical characteristics
In July 2007, French amateur astronomer René Roy obtained a rotational lightcurve from photometric observations, giving a rotation period of 16 hours with a brightness variation of 0.6 magnitude ({{{1}}}).[8] 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 ({{{1}}}).[7]
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.[4][5][6] 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.[3]
Naming
This minor planet is named after the site where ESO's discovering La Silla Observatory is situated. La Silla is a 2400-metre mountain on the outskirts of the Atacama desert, north of the city of La Serena in northern Chile.[2][11] The official naming citation was published by the Minor Planet Center on 1 December 1979 (M.P.C. 5039).[12]
References
- ↑ 1.0 1.1 1.2 1.3 "JPL Small-Body Database Browser: 2187 La Silla (1976 UH)". Jet Propulsion Laboratory. https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2002187.
- ↑ 2.0 2.1 2.2 Schmadel, Lutz D. (2007). "(2187) la Silla". Dictionary of Minor Planet Names – (2187) La Silla. Springer Berlin Heidelberg. p. 178. doi:10.1007/978-3-540-29925-7_2188. ISBN 978-3-540-00238-3.
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 "LCDB Data for (2187) La Silla". Asteroid Lightcurve Database (LCDB). http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=2187%7CLa%20Silla.
- ↑ 4.0 4.1 4.2 4.3 Mainzer, A.; Grav, T.; Masiero, J.; Hand, E.; Bauer, J.; Tholen, D. et al. (November 2011). "NEOWISE Studies of Spectrophotometrically Classified Asteroids: Preliminary Results". The Astrophysical Journal 741 (2): 25. doi:10.1088/0004-637X/741/2/90. Bibcode: 2011ApJ...741...90M.
- ↑ 5.0 5.1 5.2 Masiero, Joseph R.; Mainzer, A. K.; Grav, T.; Bauer, J. M.; Cutri, R. M.; Dailey, J. et al. (November 2011). "Main Belt Asteroids with WISE/NEOWISE. I. Preliminary Albedos and Diameters". The Astrophysical Journal 741 (2): 20. doi:10.1088/0004-637X/741/2/68. Bibcode: 2011ApJ...741...68M. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2011ApJ...741...68M. Retrieved 13 December 2016.
- ↑ 6.0 6.1 6.2 6.3 Usui, Fumihiko; Kuroda, Daisuke; Müller, Thomas G.; Hasegawa, Sunao; Ishiguro, Masateru; Ootsubo, Takafumi et al. (October 2011). "Asteroid Catalog Using Akari: AKARI/IRC Mid-Infrared Asteroid Survey". Publications of the Astronomical Society of Japan 63 (5): 1117–1138. doi:10.1093/pasj/63.5.1117. Bibcode: 2011PASJ...63.1117U. (online, AcuA catalog p. 153)
- ↑ 7.0 7.1 7.2 Waszczak, Adam; Chang, Chan-Kao; Ofek, Eran O.; Laher, Russ; Masci, Frank; Levitan, David et al. (September 2015). "Asteroid Light Curves from the Palomar Transient Factory Survey: Rotation Periods and Phase Functions from Sparse Photometry". The Astronomical Journal 150 (3): 35. doi:10.1088/0004-6256/150/3/75. Bibcode: 2015AJ....150...75W. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2015AJ....150...75W. Retrieved 13 December 2016.
- ↑ 8.0 8.1 Behrend, Raoul. "Asteroids and comets rotation curves – (2187) La Silla". Geneva Observatory. http://obswww.unige.ch/~behrend/page4cou.html#002187.
- ↑ Veres, Peter; Jedicke, Robert; Fitzsimmons, Alan; Denneau, Larry; Granvik, Mikael; Bolin, Bryce et al. (November 2015). "Absolute magnitudes and slope parameters for 250,000 asteroids observed by Pan-STARRS PS1 - Preliminary results". Icarus 261: 34–47. doi:10.1016/j.icarus.2015.08.007. Bibcode: 2015Icar..261...34V. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2015Icar..261...34V. Retrieved 13 December 2016.
- ↑ 10.0 10.1 "2187 La Silla (1976 UH)". Minor Planet Center. https://www.minorplanetcenter.net/db_search/show_object?object_id=2187.
- ↑ "About La Silla – General Information". ESO – European Southern Observatory. http://www.eso.org/sci/facilities/lasilla/site/aboutls.html.
- ↑ "MPC/MPO/MPS Archive". Minor Planet Center. https://www.minorplanetcenter.net/iau/ECS/MPCArchive/MPCArchive_TBL.html.
External links
- Asteroid Lightcurve Database (LCDB), query form (info )
- Dictionary of Minor Planet Names, Google books
- Asteroids and comets rotation curves, CdR – Observatoire de Genève, Raoul Behrend
- Discovery Circumstances: Numbered Minor Planets (1)-(5000) – Minor Planet Center
- 2187 La Silla at AstDyS-2, Asteroids—Dynamic Site
- 2187 La Silla at the JPL Small-Body Database
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