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Encyclopedia > Characteristics > Pluto II
CHARACTERISTICS OF PLUTON
| Characteristics | Values |
|---|---|
| Semi-major axis in astronomical units (au) | 39.54470 |
| Semi-major axis in km | 5 915 803 000 |
| Eccentricity of the orbit | 0.2490 |
| Inclination on the ecliptic | 17°.1422 |
| Inclination of the equator on the ecliptic | 122°.52 |
| Period of sidereal revolution | 247 years and 362 days |
| Rotation period | 6.39 days |
| Orbital velocity | 5 km/s |
| Apparent equatorial diameter at the smallest distance from the Earth (maximum value) | 0.1" |
| Diameter in km | 2390 km |
| Equatorial diameter (Earth=1) | 0.1874 |
| Visual magnitude at the opposition | 15.1 |
| Mass (Sun=1) | 1/156 000 000 |
| Mass (Earth=1) | 0.0021 |
| Mass Pluto+Charon (Sun=1) | 1/135 000 000 |
| Mass Pluto+Charon (Pluto=1) | 1.156 |
| Density (water=1) | 1.73 |
| Gravity at the surface (Earth=1) | 0.06 |
| Escape velocity | 1220 m/s |
| Reflectivity (geometric albedo) | 0.3 |
| Surface temperature | -236°C |
| Atmosphere | tenuously nitrogen and methane |
| Nature of the surface | frozen methane |
Reconstitution of the surface of Pluto after the pictures from the Hubble Space Telescope HST.
Pluto was discovered in 1930 by Tombaugh, by chance, because Pluto is not massive enough to perturbate significantly the orbit of Neptune.
