Larissa (moon)

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Larissa
Larissa.jpg
Two views of Larissa by Voyager 2
Discovery
Discovered by Harold J. Reitsema, William B. Hubbard, Larry A. Lebofsky, and David J. Tholen
Discovered on May 24, 1981
Orbital characteristics
Epoch 18 August 1989
Semi-major axis 73 548 ± 1 km
Eccentricity 0.001393 ± 0.00008
Orbital period 0.55465332 ± 0.00000001 d
Inclination 0.251 ± 0.009° (to Neptune equator)

0.205° (to local Laplace plane)

Is a moon of Neptune
Physical characteristics
Dimensions 216×204×164 km (± ~10 km)
Mass ~4.2×1018 kg (estimate)
Mean density ~1.2 g/cm3 (estimate)
Rotation period assumed synchronous
Axial tilt ~zero presumably
Albedo (geometric) 0.09
Surface temp. ~51 K mean (estimate)
Atmosphere none

Larissa or Neptune VII, is the fifth closest moon to Neptune. It is named after Larissa, a lover of Poseidon (Neptune) in Greek mythology.

It was first found by Harold J. Reitsema, William B. Hubbard, Larry A. Lebofsky and David J. Tholen based on ground-based stellar occultation observations on May 24, 1981, and given the designation S/1981 N 1 and said on 29 May 1981. The moon was refound and confirmed to be the only object in its orbit during the Voyager 2 flyby in 1989 after which it received another designation S/1989 N 2 on August 2, 1989.

Larissa is not a sphere and appears to be cratered a lot, with no sign of any geological changes. Little else is known about it.

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