21900 Orus
| Discovery [1] | |
|---|---|
| Discovered by | T. Kobayashi |
| Discovery site | Ōizumi Obs. |
| Discovery date | 9 November 1999 |
| Designations | |
| MPC designation | 21900 Orus |
| Pronunciation | /ˈɔərəs/ |
Named after | Orus (Greek mythology)[2] |
| 1999 VQ10 · 1998 VD18 | |
| Jupiter trojan [1][3] | |
| Orbital characteristics [1] | |
| Epoch 16 February 2017 (JD 2457800.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 64.59 yr (23,591 days) |
| Aphelion | 5.3099 AU |
| Perihelion | 4.9452 AU |
| 5.1275 AU | |
| Eccentricity | 0.0356 |
| 11.61 yr (4,241 days) | |
| 169.84° | |
| 0° 5m 5.64s / day | |
| Inclination | 8.4678° |
| 258.56° | |
| 180.46° | |
| Jupiter MOID | 0.0159 AU |
| Jupiter Tisserand parameter | 2.9770 |
| Physical characteristics | |
| Dimensions |
50.810±0.809[4][5] 53.87±4.08 km[6] 55.67 km (calculated)[3] |
| 13.45±0.08 h[7] | |
|
0.057 (assumed)[3] 0.075±0.014[4][5] 0.083±0.015[6] | |
| C [3][8] | |
| 9.80[6] · 9.9[4] · 10.0[1][3] · 10.12±0.32[8] | |
|
| |
21900 Orus (/ˈɔərəs/), provisional designation 1999 VQ10, is a carbonaceous Jupiter trojan of the Greek camp, approximately 53 kilometers in diameter. It was discovered on 9 November 1999, by Japanese amateur astronomer Takao Kobayashi at his private Ōizumi Observatory in Gunma Prefecture, Japan.[2] It may be visited by the spacecraft Lucy, a proposed mission concept by NASA as of 2016.[9]
The dark C-type body orbits the Sun in Jupiter's leading L4 point at a distance of 4.9–5.3 AU once every 11 years and 7 months (4,241 days). Its orbit has an eccentricity of 0.04 and an inclination of 8° with respect the plane of the ecliptic.[1] The first precovery was taken by the Digitized Sky Survey at Palomar Observatory in 1951, extending the body's observation arc by 48 years prior to its discovery.[2]
In October 2009, Orus was observed by astronomer Stefano Mottola in a photometric light-curve survey of 80 Jupiter trojans, using the 1.2-meter telescope at Calar Alto Observatory. The obtained rotational light-curve rendered a period of 13.45±0.08 hours with a brightness variation of 0.18 magnitude (U=2).[7]
According to the surveys carried out by the Japanese Akari satellite and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, the body has an albedo of 0.083 and 0.075, with a diameter of 53.9 and 50.8 kilometers, respectively.[4][5][6] The Collaborative Asteroid Lightcurve Link assumes a standard albedo for carbonaceous asteroids of 0.057 and calculates a diameter of 55.7 kilometers.[3]
The minor planet was named from Greek mythology after Orus, an Achaean warrior in Homer's Iliad. He was killed in the Trojan War by the Trojan prince Hector, after whom the largest Jupiter trojan, 624 Hektor, is named.[2] Naming citation was published on 22 February 2016 (M.P.C. 98711).[10]
References
- 1 2 3 4 5 "JPL Small-Body Database Browser: 21900 Orus (1999 VQ10)" (2016-06-10 last obs.). Jet Propulsion Laboratory. Retrieved 3 December 2016.
- 1 2 3 4 "21900 Orus (1999 VQ10)". Minor Planet Center. Retrieved 26 May 2016.
- 1 2 3 4 5 6 "LCDB Data for (21900) Orus". Asteroid Lightcurve Database (LCDB). Retrieved 26 May 2016.
- 1 2 3 4 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. arXiv:1109.6407
. Bibcode:2011ApJ...741...90M. doi:10.1088/0004-637X/741/2/90. Retrieved 26 May 2016. - 1 2 3 Grav, T.; Mainzer, A. K.; Bauer, J. M.; Masiero, J. R.; Nugent, C. R. (November 2012). "WISE/NEOWISE Observations of the Jovian Trojan Population: Taxonomy". The Astrophysical Journal. 759 (1): 10. Bibcode:2012ApJ...759...49G. doi:10.1088/0004-637X/759/1/49. Retrieved 3 December 2016.
- 1 2 3 4 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. Bibcode:2011PASJ...63.1117U. doi:10.1093/pasj/63.5.1117. Retrieved 26 May 2016.
- 1 2 Mottola, Stefano; Di Martino, Mario; Erikson, Anders; Gonano-Beurer, Maria; Carbognani, Albino; Carsenty, Uri; et al. (May 2011). "Rotational Properties of Jupiter Trojans. I. Light Curves of 80 Objects". The Astronomical Journal. 141 (5): 32. Bibcode:2011AJ....141..170M. doi:10.1088/0004-6256/141/5/170. Retrieved 26 May 2016.
- 1 2 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. arXiv:1506.00762. Bibcode:2015Icar..261...34V. doi:10.1016/j.icarus.2015.08.007. Retrieved 26 May 2016.
- ↑ Dreier, Casey; Lakdawalla, Emily (30 September 2015). "NASA announces five Discovery proposals selected for further study". The Planetary Society. Retrieved 1 February 2016.
- ↑ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 26 May 2016.
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
- List of Jupiter Trojans – Minor Planet Center
- Discovery Circumstances: Numbered Minor Planets (20001)-(25000) – Minor Planet Center
- 21900 Orus at the JPL Small-Body Database
