S/2003 J 2
S/2003 J 2 is a retrograde irregular satellite of Jupiter. The moon was discovered on 5 February 2003 by a team of astronomers from the University of Hawaii led by Scott S. Sheppard and David C. Jewitt, and was later announced on 4 March 2003. It was initially thought to be Jupiter's outermost known moon until recovery observations disproved this in 2020.
S/2003 J 2 imaged by the Canada-France-Hawaii Telescope during follow-up observations in February 2003 | |
| Discovery | |
|---|---|
| Discovered by | Scott S. Sheppard et al. |
| Discovery site | Mauna Kea Obs. |
| Discovery date | 5 February 2003 |
| Orbital characteristics | |
| Epoch 17 December 2020 (JD 2459200.5) | |
| Observation arc | 16.42 yr (5,996 d) |
| Earliest precovery date | 11 December 2001 |
| 0.1373976 AU (20,554,390 km) | |
| Eccentricity | 0.2776569 |
| –1.65 yr (–602.02 d) | |
| 114.43587° | |
| 0° 35m 52.742s / day | |
| Inclination | 149.20392° (to ecliptic) |
| 50.46976° | |
| 224.95527° | |
| Satellite of | Jupiter |
| Group | Ananke group |
| Physical characteristics | |
Mean diameter | ≈2 km |
| Albedo | 0.04 (assumed) |
| 23.2 | |
| 16.7 | |
S/2003 J 2 is about 2 km (1.2 mi) in diameter, and orbits Jupiter at an average distance of about 20,600,000 kilometers (20.6 gigametres (0.138 AU)) in roughly 600 days, at an inclination of around 149° to the ecliptic and with an eccentricity of 0.28. The moon was initially assumed to be part of the Pasiphae group, but is now known to be part of the Ananke group after it was recovered in 2020.
The moon was considered lost until 2020, when it was recovered by Sheppard and independently by amateur astronomer Kai Ly. The recovery of the moon was announced by the Minor Planet Center on 26 January 2021.