| Known Space -- Sol -- Neptune -- | Proteus |
Proteus is the sixth of Neptune's satellites. Like all six of Neptune's small satellites, is one of the darkest objects in the solar system -- "as dark as soot" is not too strong of a description. Like Saturn's satellite, Phoebe, it reflects only 6 percent of the sunlight that strikes it. It is about as large as a satellite can be without being pulled into a spherical shape by its own gravity. Proteus is irregularly shaped and shows no sign of any geological modification.
Orbital Distance: 117,600 km (circular orbit) Eccentricity: 0.000 Local Year: 1.100 days (1d 2h 24m 0s) Orbital Velocity: 7.636 km/s Inclination: 0° Local Day: 1.100 days (1d 2h 24m 0s) Axial Tilt: n/a Diameter: 418 km Composition: Rock and Ice Density: 1.76 g/cm3 Mass: 6.73 x 1016 tonnes (11/million earths) Gravity: 0.01 G Escape Velocity: 0.207 km/s Area: 550,000 km2 Surface Material: Dark soil and ice Atmosphere: None Pressure: None Albedo: 0.06 Temperature: ???°C |