Known Space -- Sol -- Saturn -- | Hyperion |
Hyperion is the sixteenth, and one of the smallest, moons of Saturn. Like most of Saturn's moons, Hyperion's low density indicates that it is composed of water ice with only a small amount of rock. But unlike most of Saturn's moons, Hyperion has a low albedo (0.2 - 0.3) indicating that it is covered by at least a thin layer of dark material. This may be material from Phoebe (which is much darker) that got past Iapetus.
Hyperion has a pock-marked body and is the largest irregularly shaped satellite ever observed. Hyperion might have had a major collision which blew part of the moon away. Its eccentric orbit makes it subject to gravitational forces from Saturn which have set it tumbling out of control. The moon's rotational period is not constant and varies from one orbit to the next. The largest crater on its surface is approximately 120 kilometers in diameter and 10 kilometers deep. The irregular shape of Hyperion and evidence of bombardment by meteors makes it appear to be the oldest surface in the Saturn system.
Orbital Distance: 1,481,000 km (average) Eccentricity: 0.104 Local Year: 21.277 days (21d 6h 38m 19s) Orbital Velocity: 5.062 km/s Inclination: 0.43° Local Day: Chaotic (variable) Axial Tilt: n/a Diameter: 410 km x 260 km x 220 km Composition: Mainly ice Density: 1.45 g/cm3 Mass: 1.77 x 1016 tonnes (3/million earths) Gravity: 0.006 G Escape Velocity: 0.108 km/s Area: 257,000 km2 Surface Material: Ices Atmosphere: None Pressure: None Albedo: 0.30 Temperature: ???°C |