Lysithea (moon)

Lysithea /laɪˈsɪθiə/ 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.[7]

Lysithea

Discovery
Discovered by	S. B. Nicholson
Discovery date	July 6, 1938[1]
Designations
Designation	Jupiter
Pronunciation	/laɪˈsɪθiə/[2][3]
Named after	Λυσιθέα Lysithea
Adjectives	Lysithean /laɪˈsɪθiən/[4]
Orbital characteristics [5]
Semi-major axis	11717000 km
Eccentricity	0.112
Orbital period	+259.2 days
Mean anomaly	329.1°
Inclination	28.30°
Longitude of ascending node	5.5°
Argument of perihelion	49.5°
Satellite of	Jupiter
Group	Himalia group
Physical characteristics
Mean diameter	38 km
Mass	6.3×1016 kg
Mean density	2.6 g/cm3 (assumed)[6]
Surface gravity	~0.013 m/s2 (0.001 g)
Escape velocity	~0.022 km/s
Albedo	0.04 (assumed)[6]
Temperature	~124 K
Apparent magnitude	18.2

Lysithea did not receive its present name until 1975; before then, it was simply known as Jupiter X. It was sometimes called "Demeter"[8] 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°.[9] Its orbital elements are as of January 2000. They are continuously changing due to solar and planetary perturbations.