(612093) 1999 LE31, prov. designation: 1999 LE31, is a centaur and damocloid on a retrograde and eccentric orbit from the outer region of the Solar System. It was first observed on 12 June 1999, by astronomers with the LINEAR program at the Lincoln Lab's ETS near Socorro, New Mexico, in the United States.[1] The unusual object measures approximately 17 kilometers (11 miles) in diameter.[2][3]
![]() Orbital diagram of the orbit of 1999 LE31 | |
Discovery[1] | |
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Discovered by | LINEAR |
Discovery site | Lincoln Lab ETS |
Discovery date | 12 June 1999 |
Designations | |
MPC designation | (612093) 1999 LE31 |
Alternative designations | 1999 LE31 |
Minor planet category | centaur[2] · damocloid[3] unusual[4] · distant[1] |
Orbital characteristics[2] | |
Epoch 27 April 2019 (JD 2458600.5) | |
Uncertainty parameter 2 | |
Observation arc | 19.23 yr (7,022 d) |
Aphelion | 11.913 AU |
Perihelion | 4.3396 AU |
Semi-major axis | 8.1265 AU |
Eccentricity | 0.4660 |
Orbital period (sidereal) | 23.17 yr (8,462 d) |
Mean anomaly | 316.77° |
Mean motion | 0° 2m 33s / day |
Inclination | 151.81° |
Longitude of ascending node | 292.12° |
Argument of perihelion | 32.319° |
Jupiter MOID | 0.517 AU |
TJupiter | -1.3090 |
Physical characteristics | |
Mean diameter | 16.8±4.2 km[2][3] |
Geometric albedo | 0.056±0.026[2][3] |
Spectral type | B–R = 1.20[3] |
Absolute magnitude (H) | 12.5[1][2] |
1999 LE31 orbits the Sun at a distance of 4.3–11.9 AU once every 23 years and 2 months (8,462 days; semi-major axis of 8.13 AU). Its orbit has an eccentricity of 0.47 and an inclination of 152° with respect to the ecliptic.[2]
It spends most of its orbit located in the outer Solar System between Jupiter and Uranus,[5] and like all centaurs, has an unstable orbit caused by the gravitational influence of the giant planets. Due to this, it must have originated from elsewhere, most likely outside Neptune.[5] It is both a Jupiter and Saturn-crossing minor planet.[2] Of over half a million known minor planets, 1999 LE31 is one of about 60 that has a retrograde orbit.[6]
1999 LE31 is approximately 16.8 km in diameter.[2][3] It came to perihelion (closest approach to the Sun) in December 1998.[7] It was last observed in 2000, and will next come to perihelion in February 2022.[2]
This asteroid has been recorded at such observatories as:[1]
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