Thalassa (moon) facts for kids
Naiad or Thalassa as seen by Voyager 2
(smearing has caused excessive elongation)
|Discovered by||Richard J. Terrile and Voyager Imaging Team|
|Discovered in||September 1989|
|Semi-major axis||50 075 ± 1 km|
|Eccentricity||0.0002 ± 0.0002|
|Orbital period||0.31148444 ± 0.00000006 d|
|Inclination||0.21 ± 0.02° (to Neptune equator)
0.21° (to local Laplace plane)
|Is a moon of||Neptune|
(based on assumed density)
|Mean density||~1.2 g/cm3 (estimate)|
|Rotation period||assumed synchronous|
|Axial tilt||~zero presumably|
|Surface temp.||~51 K mean (estimate)|
Thalassa was discovered sometime before mid-September, 1989 from the images taken by the Voyager 2 probe. It was given the designation S/1989 N 5. The discovery was said (IAUC 4867) on September 29, 1989, 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.
Thalassa is not a sphere and shows no sign of any geological changes. Unusually for a non-spherical moon, it appears to be disk-shaped.
Thalassa (moon) Facts for Kids. Kiddle Encyclopedia.