Naiad (moon)

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Naiad
Naiad Voyager.png
Naiad or Thalassa as seen by Voyager 2
(smearing has caused excessive elongation)
Discovery
Discovered by Voyager Imaging Team
Discovered in September 1989
Orbital characteristics
Epoch 18 August 1989
Semi-major axis 48 227 ± 1 km
Eccentricity 0.0004 ± 0.0003
Orbital period 0.2943958 ± 0.0000002 d
Inclination 4.75 ± 0.03° (to Neptune equator)

4.75° (to local Laplace plane)

Is a moon of Neptune
Physical characteristics
Dimensions 96×60×52 km
Mass ~1.9×1017 kg
(based on assumed density)
Mean density ~1.2 g/cm3 (estimate)
Rotation period assumed synchronous
Axial tilt ~zero presumably
Albedo (geometric) 0.07
Surface temp. ~51 K mean (estimate)
Atmosphere none

Naiad or Neptune III is the closest moon to Neptune named after the Naiads of Greek legend. It was found 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. Naiad is not a sphere and probably has not been changed by any internal geological processes after its formation. It orbits about 23,500 km above Neptune's cloud tops.

Since the Voyager 2 flyby, the Neptune system has been studied a lot from ground-based observatories and the Hubble Space Telescope as well. In 2002-03, Keck telescope looked at the system using adaptive optics and detected easily the biggest four closer satellites. Thalassa was found with some image processing, but Naiad was not located.

Other websites[change | edit source]

A simulated view of Naiad orbiting Neptune with the Sun in the distance.