| Orbital Elements | ||
| ||
| Mean distance from Sun | 2,870,990,000 km | = 19.1914 astronomical units |
| Perihelion distance | 2,741,300,000 km | = 18.3245 astronomical units |
| Aphelion distance | 3,003,620,000 km | = 20.078 astronomical units |
| Eccentricity of orbit | 0.0461 | |
| Inclination of orbit | 0.774° | relative to Earth's orbit |
| Period of orbit | 84.01 years | |
| Synodic period | 370 days | relative to Earth |
| Mean orbital speed | 6.81 km/s | |
| Minimum orbital speed | 6.49 km/s | |
| Maximum orbital speed | 7.11 km/s | |
| Physical Properties | ||
| ||
| Mean diameter | 50,724 km | = 4 Earth diameters |
| Equatorial radius | 25,559 km | |
| Oblateness | 1/45 | |
| Mass | 8.686 x 1025 kg | = 14.535 Earth masses |
| Mean density | 1.29 g/cm3 | |
| Rotational period | 17.9 hours | |
| Inclination of axis | 97.86° | relative to the axis of its orbit |
| Gravity at cloud tops | 7.77 m/s2 | |
| Escape speed | 21.3 km/s | from cloud tops |
| Visual geometric albedo | 0.51 | |
| Visual magnitude (Vo) | 5.52 | maximum, as seen from Earth |
| Mean visible cloud temperature | -193°C | |
| Atmospheric pressure | 1.2 bars | at cloud tops |
| Atmospheric Composition | |
| |
| Hydrogen (H2) | 83% |
| Helium (He) | 15% |
| Methane (CH4) | 2% |
Moons
Five medium-size moons and more than 20 small moons.
To my Space and Science home page
for more about the Solar System
Jeff Root
October 12, 2003