Themisto (moon)
Rediscovery images of Themisto taken by the UH88 telescope in November 2000 | |
| Discovery | |
|---|---|
| Discovered by | Charles T. Kowal (1975) Elizabeth P. Roemer (1975) Scott S. Sheppard (2000) David C. Jewitt (2000) Yanga R. Fernández (2000) Eugene A. Magnier (2000) |
| Discovery site | Palomar Observatory Mauna Kea Observatory (rediscovery) |
| Discovery date | 30 September 1975 21 November 2000 (rediscovery) |
| Designations | |
Designation | Jupiter XVIII |
| Pronunciation | /θəˈmɪstoʊ/ |
Named after | Θεμιστώ Themistō |
| S/2000 J 1 S/1975 J 1 | |
| Adjectives | Themistoan /θɛməˈstoʊ.ən/ Themistoian /θɛməˈstoʊ.iən/ |
| Orbital characteristics | |
| Epoch 23 March 2018 (JD 2458200.5) | |
| Observation arc | 42.54 yr (15,536 days) |
| 0.0494401 AU (7,396,130 km) | |
| Eccentricity | 0.2522112 |
| +129.95 d | |
| 2.39396° | |
| 2° 46m 13.369s / day | |
| Inclination | 45.28121° (to ecliptic) |
| 192.64162° | |
| 241.25168° | |
| Satellite of | Jupiter |
| Group | (own group) |
| Physical characteristics | |
| 9 km 16.4 km | |
| Albedo | 0.04 (assumed) |
| 21.0 | |
| 12.9 13.06±0.34 (V) | |
Themisto (/θəˈmɪstoʊ/), also known as Jupiter XVIII, is a small prograde irregular satellite of Jupiter. It was discovered in 1975, subsequently lost, and rediscovered in 2000.