Neptune
Planet Profile
Mass (kg)............................................1.02 x 10^26
Diameter (km)........................................49528
Mean density (kg/m^3) ...............................1640
Escape velocity (m/sec)..............................23300
Average distance from Sun (AU).......................30.06
Rotation period (length of day in Earth hours).......19.1
Revolution period (length of year in Earth years)....164.8
Obliquity (tilt of axis in degrees)..................29.6
Orbit inclination (degrees)..........................1.77
Orbit eccentricity (deviation from circular).........0.009
Mean temperature (K).................................48
Visual geometric albedo (reflectivity)...............0.51
Atmospheric components...............................74% hydrogen,
25% helium,
1% methane (at depth)
Rings................................................Rings are
narrow, and contain concentrations of
particles called ring arcs
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