Iapetus

More Views

Iapetus
Iapetus is the third-largest natural satellite of Saturn, eleventh-largest in the Solar System, and the largest body in the Solar System known not to be in hydrostatic equilibrium. Iapetus is best known for its dramatic 'two-tone' coloration. Discoveries by the Cassini mission in 2007 revealed several other unusual features, such as a massive equatorial ridge running three-quarters of the way around the moon. The low density of Iapetus indicates that it is mostly composed of ice, with only a small (~20%) amount of rocky materials. Unlike most of the large moons, its overall shape is neither spherical nor ellipsoid, but has a bulging waistline and squashed poles; also, its unique equatorial ridge (see below) is so high that it visibly distorts Iapetus's shape even when viewed from a distance. These features often lead it to be characterized as walnut-shaped. Iapetus (moon) - Wikipedia, the free encyclopedia
Additional Information

Additional Information

Short Description Iapetus is the third-largest natural satellite of Saturn, eleventh-largest in the Solar System, and the largest body in the Solar System known not to be in hydrostatic equilibrium. Iapetus is best known for its dramatic 'two-tone' coloration. Discoveries by the Cassini mission in 2007 revealed several other unusual features, such as a massive equatorial ridge running three-quarters of the way around the moon. The low density of Iapetus indicates that it is mostly composed of ice, with only a small (~20%) amount of rocky materials. Unlike most of the large moons, its overall shape is neither spherical nor ellipsoid, but has a bulging waistline and squashed poles; also, its unique equatorial ridge (see below) is so high that it visibly distorts Iapetus's shape even when viewed from a distance. These features often lead it to be characterized as walnut-shaped. Iapetus (moon) - Wikipedia, the free encyclopedia
Discovered by Giovanni Domenico Cassini
Discovery date October 25, 1671
Type Moon
AddInfo Saturn VIII
Satellite of Saturn
Orbit Prograde
Rotation Synchronous
Apoapsis 07 3 662 000 km
Periapsis 07 3 460 600 km
Semi-major axis 07 3 560 820 km
Distance from Sun 01 9.554 909 au /24
Eccentricity 0.028 612 5 
Orbital period 79.321 5 days
Orbital speed 01 3.26 km/s
Inclination to the ecliptic 017.28°
Inclination to the equator 015.47°
Diameter/Size 04 1 436 km
Dimensions 1.492.0 × 1.492.0 × 1.424 km 
Mass 1021×1.805 635 kg
Density 01 1.088 ± 0.013 g/cm3
Surface gravity  0.223 m/s2
Escape velocity 03 573 m/s
Rotation period 79.321 5 days
Axial tilt
Albedo geometric 0.05 – 0.5
Temperature min 02 90 K
Temperature mean 03 110 K
Temperature max 03 130 K
Apparent magnitude 10.2 – 11.9
Comments