Adjective(s) Unknown
Orbital properties
Aphelion/apoapsis Unknown
Perihelion/periapsis Unknown
Semi-major axis 294 619 (0.001969 AU)
Orbital eccentricity 0.0001
Orbital period 1.887802 days
Average orbital speed 25 km/s
Physical properties
Radius 531.1 km
Mass 6.174 49 x 10^20 kg (1.03×10^−4 earth masses)
Mean density 0.98 g/cm³
Escape velocity 0.394 km/s
Rotation period Synchronous with Saturn
Average surface temperature 50.627 K ( -222 °C)
Apparent magnitude 10.2
Moons 0
Tethys is a moon of Saturn. It was discovered by Giovanni Cassini in 1684 and is named after titan Tethys of Greek mythology. Tethys' low density suggests that it is made mostly of frozen water ice. Tethys has many craters, the largest one being named Odysseus Tethys has been approached by several space probes including Pioneer 11 (1979), Voyager 1 (1980), Voyager 2 (1981), and Cassini since 2004.