 | |
| Discovery | |
|---|---|
| Discovered by | S. B. Nicholson |
| Discovery date | July 6, 1938[1] |
| Mean orbit radius | 11,720,000 km[2] |
| Eccentricity | 0.11[2] |
| Orbital period | 259.20 d (0.69 a)[2] |
| Average orbital speed | 3.29 km/s |
| Inclination | 28.30° (to the ecliptic) 25.77° (to Jupiter's equator)[2] |
| Satellite of | Jupiter |
| Physical characteristics | |
| Mean radius | 18 km[3] |
| Surface area | ~4100 km² |
| Volume | ~24,400 km³ |
| Mass | 6.3 × 1016 kg |
| Mean density | 2.6 g/cm³ (assumed)[3] |
| Equatorial surface gravity | ~0.013 m/s2 (0.001 g) |
| Escape velocity | ~0.022 km/s |
| Albedo | 0.04 (assumed)[3] |
| Temperature | ~124 K |
| | |
Lysithea (pronounced /laɪˈsɪθiə/ lye-SITH-ee-ə, /lɨˈsɪθiə/ li-SITH-ee-ə, or as in Greek Λυσιθέα) is a prograde irregular satellite of Jupiter. It was discovered by Seth Barnes Nicholson in 1938 at Mount Wilson Observatory[1] and is named after the mythological Lysithea, daughter of Oceanus and one of Zeus' lovers.[4]
Lysithea didn't receive its present name until 1975; before then, it was simply known as Jupiter X. It was sometimes called "Demeter"[5] from 1955 to 1975.
It belongs to the Himalia group, five moons orbiting between 11 and 13 Gm from Jupiter at an inclination of about 28.3°.[2] Its orbital elements are as of January 2000. They are continuously changing due to Solar and planetary perturbations.
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