 Neptune is the eighth planet in order of
distance from the Sun and the fourth one for dimensions.Neptune was discovered in 1846 by J.G. Galls, thanks to the calculations on the perturbations of the Uranus' orbit performed independently by J.C. Adams and U. Le Verrier. The planet is wound by an atmosphere of green-blue color, composed by hydrogen, methane and acetylene. Such atmosphere shows a structure with bands parallel to the equator, interrupted by some darkest spots, which correspond to rotatory perturbations ample to 10.000 km, and by clear cloudy formations along the parallels at high altitude. The temperature of the surface is probably about -220°C. Thanks to the probe Voyager 2, that approached Neptune in 1989, a magnetic field was individualized, whose axis is inclinated of 50° in comparison to the axis of rotation, and three rings of dusts were discovered. Neptune is the center of a system of eight satellites. |
Average distance from the Sun | 4.496.600.000 km |
|---|---|---|
| Longest distance from the Sun | 4.537.000.000 km | |
| Shortest distance from the Sun | 4.456.000.000 km | |
| Period of revolution | 164,8 years | |
| Period of rotation | 16 hours, 5' | |
| Average orbital velocity | 5,4 km/s | |
| Inclination of the axis | 28° 48' | |
| Inclination of the orbit compared to the ecliptic | 1,8° | |
| Eccentricity of the orbit | 0,009 | |
| Equatorial ray | 24.750 km | |
| Deflection | 0,02 | |
| Mass | 1,06 x 10^26 kg | |
| Density | 1,76 kg/dm³ | |
| Albedo | 0,53 |
