S/2018 J 2
S/2018 J 2 is a small outer natural satellite of Jupiter discovered by Scott S. Sheppard on 12 May 2018, using the 4.0-meter Víctor M. Blanco Telescope at Cerro Tololo Observatory, Chile. It was announced by the Minor Planet Center four years later on 20 December 2022, after observations were collected over a long enough time span to confirm the satellite's orbit. The satellite has been found in precovery observations as early as 27 March 2003.
| Discovery | |
|---|---|
| Discovered by | Scott S. Sheppard |
| Discovery site | Cerro Tololo Obs. |
| Discovery date | 12 May 2018 |
| Orbital characteristics | |
| Epoch 9 August 2022 (JD 2459800.5) | |
| Observation arc | 19.48 yr (7,115 d) |
| Earliest precovery date | 27 March 2003 |
| 0.0766555 AU (11,467,500 km) | |
| Eccentricity | 0.1184102 |
| +250.88 days | |
| 99.239° | |
| 1° 26m 5.896s / day | |
| Inclination | 29.40421° (to ecliptic) |
| 66.06734° | |
| 342.09685° | |
| Satellite of | Jupiter |
| Group | Himalia group |
| Physical characteristics | |
Mean diameter | ≈3 km |
| Albedo | 0.04 (assumed) |
| 23.3 | |
| 16.5 | |
S/2018 J 2 is part of the Himalia group, a tight cluster of prograde irregular moons of Jupiter that follow similar orbits to Himalia at semi-major axes between 11–12 million km (6.8–7.5 million mi) and inclinations between 26–31°. With an estimated diameter of 3 km (1.9 mi) for an absolute magnitude of 16.5, it is among the smallest known members of the Himalia group.