Jupiter | 0.51 | 120 K | 13.06 km s-1 | naked eye planet | 6.7 × 109 cm | i = 1°18'18" | e = 0.048 | 398.9 days | 0.065 (from Pioneer 10) | for many centuries | 3°.1 | 35 megabar | | 15° to the rotational axis (data from Pioneer 10) | primarily H2 (85%) and He (14%), with traces of methane, ammonia | 2.7 that of Earth | 0.1 Jupiter radius from the center of the planet (data from Pioneer 10) | 9h50m at equator; 9h55m at polar regions (see Systems I and II longitude). | Mostly made of various light elements such as gases and simple compounds | 4 gauss (data from Pioneer 10) | metallic hydrogen in a pressure-ionized liquid phase | | 5.203 AU | brighter than 5 | 1.90 × 1030 g = 318 MEarth | 7.135 × 109 cm = 11 REarth | epicycloidal | 11.86 years | Jovian planet | Fifth planet from the Sun. It is more massive than all other planets and satellites combined; if it were about 80 times more massive, it would become self-luminous due to fusion reactions. The heat flux to from the center to the surface is mainly convective. For both Jupiter and Saturn it is necessary to invoke a substantial source of internal heating (presumably gravitational contraction) to account for the surface temperature (Jupiter radiates about 2 1/2 times as much heat as it receives from the Sun). Jupiter's surface shows pronounced horizontal striations: the light layers (zones) are at a slightly higher altitude and about 15° cooler than the dark layers (belts). It is surrounded by a partial torus of atomic H in the orbit of Io. Thirteen satellites, the four outermost of which have retrograde motion, high eccentricity, and high inclination. (Jupiter XIII, discovered in 1974, has a period of 239 days; i = 26°.7, e = 0.147.) | Vesc = 61 km s-1 | 5 × 104 K |