Naiad (moon)
Naiad or Thalassa as seen by Voyager 2 (elongation is due to smearing)
|
|
| Discovery | |
|---|---|
| Discovered by | Voyager Imaging Team |
| Discovery date | September 1989 |
| Orbital characteristics | |
| Epoch 18 August 1989 | |
| 48 227 ± 1 km | |
| Eccentricity | 0.0004 ± 0.0003 |
| 0.2943958 ± 0.0000002 d | |
| Inclination |
|
| Satellite of | Neptune |
| Physical characteristics | |
| Dimensions | 96×60×52 km |
|
Mean radius
|
33 ± 3 km |
| Volume | ~1.5×105km³ |
| Mass | ~1.9×1017 kg (based on assumed density) |
|
Mean density
|
~1.3 g/cm³ (estimate) |
| ~0.012 m/s2 | |
| ~0.028 km/s | |
| synchronous | |
| zero | |
| Albedo | 0.07 |
| Temperature | ~51 K mean (estimate) |
| 23.9 | |
Naiad (/ˈneɪ.əd/ NAY-əd or /ˈnaɪ.əd/ NY-əd; Greek: Ναϊάδ-ες), also known as Neptune III, is the innermost satellite of Neptune, named after the Naiads of Greek legend.
Naiad was discovered sometime before mid-September 1989 from the images taken by the Voyager 2 probe. The last moon to be discovered during the flyby, it was designated S/1989 N 6. The discovery was announced on September 29, 1989, in the IAU Circular No. 4867, but the text only talks of "25 frames taken over 11 days", giving a discovery date of sometime before September 18. The name was given on 16 September 1991.
Naiad is irregularly shaped and probably has not been modified by any internal geological processes since its formation. It is likely that it 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.
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