Mass Radius Mean density Visual geometric albedo (1020 kg) (km) (kg/m3) Naiad (NIII) 0.002 48 x 30 x 26 0.07 Thalassa (NIV) 0.004 54 x 50 x 26 0.09 Despina (NV) 0.02 90 x 74 x 64 0.09 Galatea (NVI) 0.04 102 x 92 x 72 0.08 Larissa (NVII) 0.05 108 x 102 x 84 0.09 Proteus (NVIII) 0.5 220 x 208 x 202 0.10 Triton (NI) 214. 1,353.4 2,050 0.76 Nereid (NII) 0.3 170 0.16 Halimede (NIX, S/2002 N1) 0.001 30 0.16 Sao (NXI, S/2002 N2) 0.001 20 0.16 Laomedeia (NXII, S/2002 N3) 0.001 20 0.16 Neso (NXIII, S/2002 N4) 30 Psamathe (NX, S/2003 N1 0.0002 20 0.16
Orbital Rotation Semimajor axis Period* Period Inclination Eccentricity (103 km) (Neptunian Radii) (days) (days) (degrees) Naiad (NIII) 48.227 1.948 0.294396 4.74 0.0003 Thalassa (NIV) 50.075 2.022 0.311485 0.21 0.0002 Despina (NV) 52.526 2.121 0.334655 0.07 0.0001 Galatea (NVI) 61.953 2.502 0.428745 0.05 0.0001 Larissa (NVII) 73.548 2.970 0.554654 0.20 0.0014 Proteus (NVIII) 117.647 4.751 1.122315 0.04 0.0004 Triton (NI) 354.76 14.328 5.876854R S 157.345 0.000016 Nereid (NII) 5,513.4 222.67 360.13619 7.23 0.7512 Halimede (NIX, S/2002 N1) 15730. 635.2 1879.7R 134.1 0.571 Sao (NXI, S/2002 N2) 22420. 905.3 2914.1 48.5 0.293 Laomedeia (NXII, S/2002 N3) 23570. 951.8 3167.9 34.7 0.424 Psamathe (NX, S/2003 N1 46700. 1885.8 9115.9R 137.4 0.450 Neso (NXIII, S/2002 N4) 48390. 1954.0 9374.0R 132.6 0.495*R indicates retrograde motion
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