20461 Dioretsa

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20461 Dioretsa
Discovered by Lincoln Laboratory Near-Earth Asteroid Research Team at Socorro[1]
Discovery date 8 June 1999
MPC designation 20461
Pronunciation /d.əˈrɛtsə/ dy-ə-RET-sə
1999 LD31
centaur,[1] damocloid
Orbital characteristics[1]
Epoch 2457000.5 (2014 Dec 09.0)
Aphelion 45.162 AU
Perihelion 2.390026 AU
23.776 AU
Eccentricity 0.899478
115.94 yr (42,346 days)
Inclination 160.40358° (retrograde)
Known satellites none
Physical characteristics
Dimensions 14±3 km[2]

Dioretsa (1999 LD31) is a centaur[1] discovered in 1999 notable for its unusual orbit, which is highly eccentric and retrograde. Its name is the word 'asteroid' spelled backwards to reflect this fact. It is one of twenty or so known minor planets in the Solar System that have a retrograde orbit—see the List of exceptional asteroids.

Dioretsa's orbit is otherwise similar to that of a comet. It has a perihelion of 2.4 AU and an aphelion of 45.2 AU. This has led to speculation that Dioretsa was originally an object from the Oort cloud.