Thalassa
Moon· orbits Neptune
Thalassa — moon of Neptune.
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Key facts
Mass (est.)
3.53 × 10¹⁷ kg
0.00000481 Moon masses
Radius
40 km
2% of our Moon's radius
Surface gravity
0.0147 m/s²
0% of Earth's gravity
Orbit around Neptune
7.5 hours
0.31 Earth days
Science
Physical
- Mass (estimated)
- 3.53 × 10¹⁷ kg · 0.00000481 Moon masses
- Dynamically estimated (JPL ephemeris fit) but poorly constrained (GM uncertain to ~22%). Source: JPL SSD Planetary Satellite Physical Parameters (GM NEP097).
- Radius
- 40 km · 2% of our Moon's radius
- JPL SSD Planetary Satellite Physical Parameters (mean radius)
- Density
- 1,318 kg/m³ · 1.3× water
- Estimated from the estimated mass and radius
- Surface gravity
- 0.0147 m/s² · 0% of Earth's gravity
- Estimated from the estimated mass and radius
- Escape velocity
- 34.3 m/s · 0% of Earth's escape velocity
- Estimated from the estimated mass and radius
Orbit around Neptune
- Distance from Neptune
- 50,100 km
- From JPL orbital elements
- Orbital period
- 7.46 hours
- From JPL orbital elements
- Eccentricity
- 0
- From JPL orbital elements
- Inclination to Neptune's Laplace plane
- 0.20 °
- From JPL orbital elements · The Laplace plane is the one a moon's orbit precesses about: close in it is the planet's equatorial plane, the plane of the rings, and further out it tilts toward the planet's own orbit.
Radiation & temperature
- Insolation
- 0.00112 S⊕ · 1/893 of the sunlight Earth receives
- Computed from the distance to the Sun (inverse-square; Earth's sunlight = 1), before any atmosphere.
Discovery & history
- By
- Voyager Science Team
Thalassa was discovered in 1989 by Voyager Science Team. Neptune's moons are named after sea deities and nymphs of Greek mythology. Beyond its discovery and naming, little more about it has been individually recorded.
Images
Images from open archives · credit shown per image