15810 Arawn
15810 Arawn (provisional designation 1994 JR1) is a trans-Neptunian object (TNO) from the inner regions of the Kuiper belt, approximately 133 kilometres (83 mi) in diameter. It belongs to the plutinos, the most populous class of resonant TNOs. It was named after Arawn, the ruler of the underworld in Welsh mythology, and was discovered on 12 May 1994, by astronomers Michael Irwin and Anna Żytkow with the 2.5-metre Isaac Newton Telescope at Roque de los Muchachos Observatory in the Canary Islands, Spain.
A distant view of Arawn (center) from New Horizons in November 2015. | |
| Discovery | |
|---|---|
| Discovered by | M. J. Irwin A. Żytkow |
| Discovery site | La Palma Obs. |
| Discovery date | 12 May 1994 |
| Designations | |
MPC designation | (15810) Arawn |
| Pronunciation | /ˈɑːraʊn/ |
Named after | Arawn (Welsh mythology) |
Alternative designations | 1994 JR1 |
Minor planet category | TNO · plutino |
| Orbital characteristics | |
| Epoch 16 February 2017 (JD 2457800.5) | |
| Uncertainty parameter 2 | |
| Observation arc | 21.91 yr (8,002 days) |
| Aphelion | 44.241 AU |
| Perihelion | 34.720 AU |
Semi-major axis | 39.480 AU |
| Eccentricity | 0.1206 |
Orbital period (sidereal) | 248.07 yr (90,609 days) |
Mean anomaly | 30.638° |
Mean motion | 0° 0m 14.4s / day |
| Inclination | 3.8074° |
Longitude of ascending node | 144.69° |
| 101.89° | |
| Physical characteristics | |
| Dimensions | 133 km (83 mi) 145 km (90 mi) |
Synodic rotation period | 5.47±0.33 h |
| 0.04 | |
| 7.6 | |
Arawn is unusual in that it has been observed at a much closer distance than most Kuiper belt objects, by the New Horizons spacecraft, which imaged it from a distance of 111 million km (69 million mi; 0.74 AU) in April 2016; this and its other observations have allowed its rotation period to be determined.