Larissa (moon)
Larissa from Voyager 2
|
|
| Discovery | |
|---|---|
| Discovered by | Harold J. Reitsema, William B. Hubbard, Larry A. Lebofsky, and David J. Tholen |
| Discovery date | May 24, 1981 |
| Orbital characteristics | |
| Epoch 18 August 1989 | |
| 73 548 ± 1 km | |
| Eccentricity | 0.001393 ± 0.00008 |
| 0.55465332 ± 0.00000001 d | |
| Inclination |
|
| Satellite of | Neptune |
| Physical characteristics | |
| Dimensions | 216×204×168 km (± ~10 km) |
|
Mean radius
|
97 ± 3 km |
| Volume | ~3.5×106km³ |
| Mass | ~4.2×1018 kg (estimate) |
|
Mean density
|
~1.2 g/cm³ (estimate) |
| ~0.03 m/s2 | |
| ~0.076 km/s | |
| synchronous | |
| zero | |
| Albedo | 0.09 |
| Temperature | ~51 K mean (estimate) |
| 21.5 | |
Larissa (/ləˈrɪsə/ lə-RISS-ə; Greek: Λάρισσα), also known as Neptune VII, is the fifth-closest inner satellite of Neptune. It is named after Larissa, a lover of Poseidon (Neptune) in Greek mythology and eponymous nymph of the city in Thessaly, Greece.
It was first discovered by Harold J. Reitsema, William B. Hubbard, Larry A. Lebofsky and David J. Tholen, based on fortuitous ground-based stellar occultation observations on May 24, 1981, given the temporary designation S/1981 N 1 and announced on May 29, 1981. The moon was recovered and confirmed to be the only object in its orbit during the Voyager 2 flyby in 1989 after which it received the additional designation S/1989 N 2 on August 2, 1989. The announcement by Stephen P. Synnott spoke of “10 frames taken over 5 days”, which gives a recovery date sometime before July 28. The name was given on September 16, 1991.
The fourth-largest satellite of Neptune, Larissa is irregular (non-spherical) in shape and appears to be heavily cratered, with no sign of any geological modification. Little else is known about it. It is likely that Larissa, like the other satellites inward of Triton, is a rubble pile re-accreted from fragments of Neptune's original satellites, which were smashed up by perturbations from Triton soon after that moon's capture into a very eccentric initial orbit.
...
Wikipedia