- 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 0° 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
-