Tethys
Moon· orbits Saturn
Tethys is a mid-sized, ice-rich moon of Saturn marked by the huge Odysseus impact crater and the vast Ithaca Chasma canyon.
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Key facts
Mass
6.17 × 10²⁰ kg
0.00841 Moon masses
Radius
531 km
31% of our Moon's radius
Surface gravity
0.146 m/s²
1% of Earth's
Day length
45.31 hours
Orbit around Saturn
1.89 Earth days
Science
Physical
- Mass
- 6.17 × 10²⁰ kg · 0.00841 Moon masses
- Radius
- 531 km · 31% of our Moon's radius
- Density
- 984 kg/m³ · 0.98× water
- Surface gravity
- 0.146 m/s² · 1% of Earth's
- Escape velocity
- 394 m/s · 4% of Earth's
Orbit around Saturn
- Distance from Saturn
- 4,423,379 km
- Orbital period
- 45.31 hours
- Eccentricity
- 0.001
- Inclination
- 1.10 °
Rotation
- Rotation period
- 45.31 hours
- Tidal locking
- Tidally locked to its parent
Temperature
- Mean
- 86 K (-187 °C)
Composition
- Bulk composition
- Almost pure water ice with very little rock — one of the least dense moons known.
Radiation & temperature
- Insolation
- 0.0112 S⊕ · 1% of the sunlight Earth receives
- Bond albedo
- 0.70 · reflects 70% of incoming sunlight
- Equilibrium temperature
- 67 K (-206 °C)
- Measured mean temperature
- 86 K (-187 °C)
- Greenhouse warming
- +19 K
Discovery & history
- Discovered
- March 21, 1684
- By
- Giovanni Domenico Cassini
- Method
- Visual discovery (telescopic)
- Name
- Tethys, a Titaness of the sea in Greek myth.
Giovanni Cassini discovered Tethys in 1684 from the Paris Observatory. A ball of nearly pure water ice, it carries the huge Odysseus impact basin and Ithaca Chasma, a canyon system stretching most of the way around the moon.
Images
Images from open archives · credit shown per image