Larissa (moon)

Larissa

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.

Other websites

• Larissa Profile Archived 2007-08-01 at the Wayback Machine by NASA's Solar System Exploration