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Neptune XI

Proper NameSao
DesignationNeptune XI
Primary PlanetNeptune
Family / ClassPrograde irregular moons
Orbital Period7 years, 356 days
Distance from NeptuneSemi-Major Axis: 22,381,400 km (0.15 AU)
Periapsis: 15,689,400 km (0.10 AU)
Apoapsis: 29,073,400 km (0.19 AU)
Rotation PeriodNot known
Mean Diameter44 km
27 miles

One of several small moons that orbit Neptune far from that ice giant planet, Sao is a small, irregularly shaped rock averaging some 44km in diameter. It takes its name from one of the fifty Nereids, companions of Poseidon in Greek mythology and thus a suitable name for a moon of the planet named for Poseidon's Roman equivalent, Neptune.

Sao orbits more than 22 million kilometres from Neptune, and its closest companion in the planet's moon system is Laomedeia, another small irregular moon named for one of the Nereids, following a path that takes it more than a million kilometres farther from Neptune than Sao. Sao follows a prograde orbit (that is, it orbits in the same direction as Neptune's rotation) and is inclined at more than 53° to Neptune's equator.


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