20461 Dioretsa

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20461 Dioretsa
Discovery [1]
Discovered byLINEAR
Discovery siteLincoln Lab ETS
Discovery date8 June 1999
Designations
(20461) Dioretsa
Pronunciation/daɪ.əˈrɛtsə/
Named after
Asteroid [2]
(spelled backwards)
1999 LD31
Minor planet category
centaur[3] · damocloid [4]
unusual [5] · distant [1]
Orbital characteristics [3]
Epoch 27 April 2019 (JD 2458600.5)
Uncertainty parameter 2
Observation arc2.54 yr (927 d)
Aphelion45.404 AU
Perihelion2.4021 AU
23.903 AU
Eccentricity0.8995
116.87 yr (42,686 d)
59.873°
0° 0m 30.24s / day
Inclination160.43°
297.77°
103.13°
Jupiter MOID0.1907 AU
TJupiter-1.5470
Physical characteristics
Mean diameter
14±3 km[4][6]
0.03±0.01[4][6]
Absolute magnitude (H)
13.8[1][3]

20461 Dioretsa /daɪ.əˈrɛtsə/ is a centaur and damocloid on a retrograde, cometary-like orbit from the outer Solar System. It 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.[1] The highly eccentric unusual object measures approximately 14 kilometers (8.7 miles) in diameter.[4][6] It was named Dioretsa, the word "asteroid" spelled backwards.[1]

Classification and orbit[]

Dioretsa is a member of the damocloids,[4] with a retrograde orbit and a negative TJupiter of −1.547. It is also a centaur, as its orbit has a semi-major axis in between that of Jupiter (5.5 AU) Neptune (30.1 AU).[3] The Minor Planet Center lists it as a critical object and (other) unusual minor planet due to an orbital eccentricity of more than 0.5.[5]

It orbits the Sun at a distance of 2.4–45.4 AU once every 116 years and 10 months (42,686 days; semi-major axis of 23.9 AU). Its orbit has an eccentricity of 0.90 and an inclination of 160° with respect to the ecliptic.[3] Its observation arc begins 12 months prior to its official discovery observation, with a precovery taken by Spacewatch at Steward Observatory in June 1998.[1] Currently, its orbit still has an uncertainty of 2.[3]

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.[citation needed]

Naming[]

The minor planet's name "Dioretsa" is the word "asteroid" spelled backwards, and is the first numbered of currently 99 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).[7]

Physical characteristics[]

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.[6] It has an absolute magnitude of 13.8.[3] As of 2018, Dioretsa's spectral type as well as its rotation period and shape remain unknown.[3][8]

References[]

  1. ^ Jump up to: a b c d e f "20461 Dioretsa (1999 LD31)". Minor Planet Center. Retrieved 20 November 2018.
  2. ^ Jump up to: a b Schmadel, Lutz D. (2006). "(20461) Dioretsa [24.4, 0.90, 160.2]". Dictionary of Minor Planet Names – (20461) Dioretsa, Addendum to Fifth Edition: 2003–2005. Springer Berlin Heidelberg. p. 152. doi:10.1007/978-3-540-34361-5_1728. ISBN 978-3-540-34360-8.
  3. ^ Jump up to: a b c d e f g h "JPL Small-Body Database Browser: 20461 Dioretsa (1999 LD31)" (2000-12-29 last obs.). Jet Propulsion Laboratory. Retrieved 20 November 2018.
  4. ^ Jump up to: a b c d e Johnston, Wm. Robert (7 October 2018). "List of Known Trans-Neptunian Objects". Johnston's Archive. Retrieved 20 January 2018.
  5. ^ Jump up to: a b "List Of Other Unusual Objects". Minor Planet Center. 14 November 2018. Retrieved 20 November 2018.
  6. ^ Jump up to: a b c d 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.
  7. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 20 November 2018.
  8. ^ "LCDB Data for (20461) Dioretsa". Asteroid Lightcurve Database (LCDB). Retrieved 27 June 2017.

External links[]

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