20461 Dioretsa
| Discovery [1] | |
|---|---|
| Discovered by | LINEAR |
| Discovery site | Lincoln Lab ETS |
| Discovery date | 8 June 1999 |
| Designations | |
| MPC designation | (20461) Dioretsa |
| Pronunciation | /daɪ.əˈrɛtsə/ dy-ə-RET-sə |
Named after |
Asteroid (spelled backwards)[2] |
| 1999 LD31 | |
| centaur[1] · damocloid | |
| Orbital characteristics [1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 2 | |
| Observation arc | 2.54 yr (927 days) |
| Aphelion | 45.320 AU |
| Perihelion | 2.4113 AU |
| 23.866 AU | |
| Eccentricity | 0.8990 |
| 116.59 yr (42,585 days) | |
| 55.017° | |
| 0° 0m 30.6s / day | |
| Inclination | 160.42° |
| 297.54° | |
| 102.91° | |
| Jupiter MOID | 0.1887 AU |
| Jupiter Tisserand parameter | -1.5500 |
| Physical characteristics | |
| Dimensions | 14±3 km[3] |
| 0.03±0.01[3] | |
| 13.8[1] | |
|
| |
20461 Dioretsa (/daɪ.əˈrɛtsə/ dy-ə-RET-sə), provisional designation 1999 LD31, is a distant, comet-like minor planet, classified as a highly eccentric centaur with a retrograde orbit, approximately 14 kilometers in diameter.
This centaur was discovered on 8 June 1999, by members of the LINEAR team at the Lincoln Laboratory Experimental Test Site near Socorro, New Mexico, United States.[3][4] It was named Dioretsa, the word "asteroid" spelled backwards.
Classification and orbit
Dioretsa orbits the Sun at a distance of 2.4–45.3 AU once every 116 years and 7 months (42,585 days). Its orbit has an eccentricity of 0.90 and an inclination of 160° with respect to the ecliptic.[1]
Its observation arc begins 12 months prior to its official discovery observation, with a precovery taken by Spacewatch at Steward Observatory in June 1998.[4] Currently, its orbit still has an uncertainty of 2.[1]
Retrograde orbit
An inclination of greater than 90° means that a body moves in a retrograde orbit. Dioretsa's orbit is otherwise similar to that of a comet. This has led to speculation that Dioretsa was originally an object from the Oort cloud.
Physical characteristics
Diameter and albedo
According to observations made with the 10-meter Keck Telescope, Dioretsa measures 14 kilometers in diameter and its surface has a low albedo of 0.03.[3] It has an absolute magnitude of 13.8.[1]
Lightcurve
As of 2017, Dioretsa's spectral type as well as its rotation period and shape remain unknown.[1][5]
Naming
The minor planet's name "Dioretsa" is the word "asteroid" spelled backwards, and is the first numbered of currently more than 20 known minor planets with a retrograde motion in the Solar System.[2] The approved naming citation was published by the Minor Planet Center on 1 May 2003 (M.P.C. 48396).[6]
References
- 1 2 3 4 5 6 7 8 "JPL Small-Body Database Browser: 20461 Dioretsa (1999 LD31)" (2000-12-29 last obs.). Jet Propulsion Laboratory. Retrieved 27 June 2017.
- 1 2 Schmadel, Lutz D. (2006). Dictionary of Minor Planet Names – (20461) Dioretsa, Addendum to Fifth Edition: 2003–2005. Springer Berlin Heidelberg. p. 152. ISBN 978-3-540-34360-8. Retrieved 4 April 2016.
- 1 2 3 4 Harris, Alan W.; Delbó, Marco; Binzel, Richard P.; Davies, John K.; Roberts, Julie; Tholen, David J.; et al. (October 2001). "Visible to Thermal-Infrared Spectrophotometry of a Possible Inactive Cometary Nucleus". Icarus. 153 (2): 332–337. Bibcode:2001Icar..153..332H. doi:10.1006/icar.2001.6687. Retrieved 4 April 2016.
- 1 2 "20461 Dioretsa (1999 LD31)". Minor Planet Center. Retrieved 4 April 2016.
- ↑ "LCDB Data for (20461) Dioretsa". Asteroid Lightcurve Database (LCDB). Retrieved 27 June 2017.
- ↑ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 20 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
- Discovery Circumstances: Numbered Minor Planets (20001)-(25000) – Minor Planet Center
- 20461 Dioretsa at the JPL Small-Body Database
