_2001_XR254_hst.jpg) Hubble Space Telescope image of2001 XR254 and its satellite, taken in 2007. | |
| Discovery[1][2] | |
|---|---|
| Discovered by | D. C. Jewitt S. S. Sheppard J. Kleyna |
| Discovery site | Mauna Kea Obs. |
| Discovery date | 10 December 2001 |
| Designations | |
| (524366) 2001 XR254 | |
| 2001 XR254 | |
| TNO[3] · cubewano[4][2] cold[5] | |
| Orbital characteristics[3] | |
| Epoch 27 April 2019 (JD 2458600.5) | |
| Uncertainty parameter 4 · 3[1] | |
| Observation arc | 14.26yr (5,207 d) |
| Aphelion | 44.374AU |
| Perihelion | 41.178 AU |
| 42.776 AU | |
| Eccentricity | 0.0374 |
| 279.78 yr (102,188 d) | |
| 226.02° | |
| 0° 0m 12.6s / day | |
| Inclination | 1.2309° |
| 180.01° | |
| ≈ 7 September 2120[6] ±1 month | |
| 78.868° | |
| Knownsatellites | 1(D: 140 km;P: 125.58d)[7][8] |
| Physical characteristics | |
| 221+41 −71 km(combined) 171+32 −55 km(primary) | |
| Mass | (4.055±0.048)×1018 kg[9] |
Meandensity | 1.00+0.96 −0.56 g/cm3[8][a] |
| 0.136+0.168 −0.044[8] | |
| V−I =1.06±0.12[7] | |
| 5.7[1][3] 6.05[8] | |
(524366) 2001 XR254, provisional designation2001 XR254, is atrans-Neptunian object andbinary system from the classicalKuiper belt, located in the outermost region of theSolar System. Thecubewano belongs to thecold population and measures approximately 171 kilometers (110 miles).[8] It was first observed on 10 December 2001, by astronomers at theMauna Kea Observatory, Hawaii. Its 140-kilometer sizedcompanion was discovered by theHubble Space Telescope in June 2006.[7]
2001 XR254 was discovered on 10 December 2001 byDavid C. Jewitt,Scott S. Sheppard andJan Kleyna using 2.2-meter University of Hawaii reflector onMauna Kea.[2]2001 XR254 belongs to the dynamically cold population of the classicalKuiper belt objects, with small orbital eccentricities and inclinations. Their semi-major axes reside mainly in the interval 40–45 AU.[8]
2001 XR254 is a binary consisting of two components of approximately equal size. Assuming that both components have the same albedo, the primary is estimated to be about 170 km in diameter. The size of the secondary (satellite) in this case is estimated at about 140 km. The total mass of the system is about 4×1018 kg. The average density of both components is about 1 g/cm3.[8]
| Semi-major axis (km) | Eccentricity | Period (d) | Inclination (°) |
| 9311 ± 52 | 0.5561 ± 0.0047 | 125.579 ± 0.048 | 41.08 ± 0.22 |
Thisminor planet was numbered by theMinor Planet Center on 18 May 2019 (M.P.C. 114619). As of 2025, it has not been named.[10]
The surfaces of both components of2001 XR254 appear to have a neutral color.[8]
