| Discovery[1][2][3] | |
|---|---|
| Discovered by | M. E. Schwamb |
| Discovery site | La Silla Obs. |
| Discovery date | 8 October 2010 |
| Designations | |
| (508338) 2015 SO20 | |
| 2015 SO20 · 2010 TF182 | |
| TNO[1] · E-SDO[4] distant[2] · detached extreme | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter2 | |
| Observation arc | 6.96 yr (2,543 days) |
| Aphelion | 290.09 AU |
| Perihelion | 33.164 AU |
| 161.63 AU | |
| Eccentricity | 0.7948 |
| 2054.81 yr (750,519 d) | |
| 0.0032° | |
| 0° 0m 1.8s / day | |
| Inclination | 23.451° |
| 33.619° | |
| 354.80° | |
| Physical characteristics | |
| Dimensions | 221 km (calculated)[5] 222 km (calculated)[4] |
| 0.08 (assumed)[5] 0.09 (assumed)[4] | |
| 6.5[1] · 6.7[5] | |
(508338) 2015 SO20 is an extreme trans-Neptunian object and extended scattered disc object from the outermost region of the Solar System, approximately 220 kilometers (140 miles) in diameter.
This minor planet was first observed as 2010 TF182 on 8 October 2010, by American astronomer Megan SchwambatESO's La Silla Observatory in northern Chile.[2] It has also been observed as 2015 SO20 during the Calar Alto TNO Survey (Z79) at the Calar Alto Observatory, Spain, on 20 September 2015.[3]
It orbits the Sun at a distance of 33.2–290.1 AU once every 2054 years and 9 months (semi-major axis of 161 AU). Its orbit has an eccentricity of 0.79 and an inclination of 23° with respect to the ecliptic.[1]
It is one a small number of detached objects with perihelion distances of 30 AU or more, and semi-major axes of 150 AU or more.[6] Such objects can not reach such orbits without some perturbing object, which lead to the speculation of planet nine.
Based on an absolute magnitude of 6.5 and an assumed albedo of 0.09, the Johnston's Archive calculated a mean-diameter of 222 kilometers.[4] Michael Brown estimates an albedo of 0.08 with a diameter of 221 kilometers using an absolute magnitude of 6.7. He also considers it a dwarf-planet candidate with a low probability ("possible").[5]
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| Dwarf planets (moons) |
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| Sednoids |
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