(mostly written in 2004, before the Cassini spacecraft reached Saturn)
Phoebe imaged by Cassini in 2004
(Cassini Imaging Team, SSI, JPL, ESA, NASA, apod040630)
Data for Phoebe
Discovered by William Pickering in 1898
Named after one of the daughters of Uranus and Gaea
Orbital size 12,950,000 km (about 800,000 miles) (four times larger than that of Iapetus)
Orbital eccentricity 16%
Orbital inclination 175 degrees (relative to Ecliptic plane)
Orbital period -550.48 days (retrograde)
Rotation period 9.4 hours
Diameter 220 km (135 miles)
Mass around a million times less than Earth
Density probably about that of water (Composition probably mostly ice and carbon compounds)
Surface gravity perhaps 1/300 of Earth's
Albedo (reflectivity) 5%
Probably captured carbonaceous asteroid or Kuiper Belt Object |
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