ABSTRACT
Iapetus Moon of Saturn, also designated SVIII. Discovered by Cassini in 1671, it is noted for a surface where the leading edge has an albedo of 0.02 to 0.05, and the trailing edge has an albedo of 0.5. It has been conjectured that the difference is due to the leading edge accreting dark material (possibly from Phoebe) as it orbits. Its orbit has an eccentricity of 0.028, an inclination of 14.72◦, and a semimajor axis of 3.56× 106 km. Its radius is 730 km, its mass is 1.88× 1021 kg, and its density is 1.15 g cm−3. It orbits Saturn once every 79.33 Earth days.
