以下信息转自维基百科
Name Mean diameter (km) Mass (×10^21 kg) Semi-major axis (km) Orbital period (days) Eccentricity Inclination (to pluto's equator) Discovery date
Pluto 2306 ± 20 13.05 ± 0.07 2390 6.38723 0 — 1930
Pluto I Charon 1207 ± 3 1.52 ± 0.06 19 571 ± 4 6.38723 0 (0.000% ± 0.007%) 0.00° ± 0.014° 1978
Pluto II Nix 46-137 < 0.002 48 675 ± 120 24.856 ± 0.001 ~0 (0.2% ± 0.2%) 0.04° ± 0.22° 2005
Pluto III Hydra 61-167 < 0.002 64 780 ± 90 38.206 ± 0.001 0.5% ± 0.1% 0.22° ± 0.12° 2005
[ 本帖最后由 zwhzjh 于 2008-7-27 16:11 编辑 ]