Celestial     calendar

Satellites of Neptune

(Orbital, physical and photometric data)


Name

Orbital Period
(R=Retrograde1)

Semimajor Axis2

Mass

Radius

Magnitude3

d

´103 km

1/Planet

km

m

I  Triton

5.88   R

355

2.09´10-4

1 353

+13.5

II Nereid

360.14

5 513

 

170

+19.7

V Despina

0.33

52

 

75:

+22.5

VI Galatea

0.43

62

 

80:

+22.4

VII Larissa

0.55

74

 

104´89

+22.0

VIII Proteus

1.12

118

 

218´208´201

+20.3

 

Main Astronomical Observatory

  

1 Retrograde motion: for orbital motion in the solar system, motion that is clockwise in the orbit as seen from the north pole of the ecliptic.

2 Half the length of the major axis of the ellipse; a standard element used to describe an elliptical orbit.

3 This is the mean opposition magnitude of the satellite.