Encyclopedia > Saturn > Outer satellites I
Phoebe (Saturn IX) was discovered by Pickering in 1898. It was the farthest satellite from Saturn : amazingly, it rotates around Saturn in a retrograde mode contrarily to the main satellites. It is probably a body captured by the planet Saturn.
Since 2000, large new telescopes allowed to discover new small satellites similar to Phoebe.
Characteristics | Values |
---|---|
semi-major axis | 12 893 240 km |
mean size | 220 km |
visual magnitude | 16,5 |
period of revolution | 546 days and 14 hours |
period of rotation | 9 hours and 17 minutes |
orbital velocity | 2 km/s |
inclination of the orbit on the equateur of Saturn |
174° (retrograde) |
eccentricity of the orbit | 0.1756 |
density (water=1) | 0.07 |
escape velocity | 70 m/s |
reflectivity (geometric albedo) | 0.06 |
Phoebe is especially dark. It is probably a class C asteroid (carbon) captured by Saturn.