Prometheus

Discovery
Discovered by	Collins, Voyager 1
Discovered in	October, 1980
Orbital characteristics
Semimajor axis	139,353 km *
Eccentricity	0.0024
Orbital period	0.614102 d
Inclination	0.007° (to Saturn's equator)
Is a satellite of	Saturn
Physical characteristics
Diameter	86 km (119×87×61 km)
Surface area	~136,000 km2
Volume	~527,000 km3
Mass	3.3 kg
Mean density	0.63 g/cm3
Surface gravity	~0.0081 m/s2
Escape velocity	~0.030 km/s
Rotation period	synchronous
Axial tilt	zero
Albedo	0.6
Surface temp.

min	mean	max
K	~74 K	K

Atmosphere none Prometheus (proe-mee'-thee-əs, IPA , Greek Προμηθέας) is a moon of Saturn. It was discovered in 1980 (some time before October 25) from Voyager photos, and was designated 1980 S 27. In 1985 it was officially named after Prometheus, a Titan in Greek mythology. It is also designated as Saturn XVI.

This small moon is extremely elongated, measuring about 148 by 100 by 68 km. It has several ridges and valleys and a number of impact craters of about 20 km diameter are visible, but it is less cratered than nearby Pandora, Epimetheus and Janus. From its very low density and relatively high albedo, it seems likely that Prometheus is a very porous icy body. There is a lot of uncertainty in these values, however, and so this remains to be confirmed.

Prometheus acts as a shepherd satellite for the inner edge of Saturn's F Ring. Recent images from the Cassini probe show that the Promethean gravitational field creates kinks and knots in the F Ring as the moon 'steals' material from it.

There is also an asteroid called 1809 Prometheus.

External links

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• The Planetary Society: Prometheus

Saturn's moons

Прометей (спътник) | Prometeu (satèl·lit) | Prometheus (měsíc) | Prometheus (måne) | Prometheus (Mond) | Prometeo (luna) | Prométhée (lune) | Prometej (mjesec) | Prometheus (maan) | プロメテウス (衛星) | Saturnmånen Prometheus | Prometeusz (księżyc) | Prometeu (satélite) | Прометей (спутник Сатурна) | Prometheus (mesiac) | Prometheus (måne) | Прометей (супутник) | 土卫十六