![[Montage of Jupiter and the Galilean Satellites]](/images/jupiter_family.jpg)
Jupiter Earth Ratio (Jupiter/Earth)
Mass (1024 kg) 1,898.6 5.9736 317.83
Volume (1010 km3) 143,128 108.321 1321.33
Radius (1 bar level) (km)
Equatorial 71,492 6,378.1 11.209
Polar 66,854 6,356.8 10.517
Volumetric mean radius (km) 69,911 6,371.0 10.973
Ellipticity 0.06487 0.00335 19.36
Mean density (kg/m3) 1,326 5,515 0.240
Gravity (eq., 1 bar) (m/s2) 23.12 9.78 2.364
Escape velocity (km/s) 59.5 11.19 5.32
GM (x 106 km3/s2) 126.686 0.3986 317.8
Bond albedo 0.343 0.306 1.12
Visual geometric albedo 0.52 0.367 1.42
Visual magnitude V(1,0) -9.40 -3.86 -
Solar irradiance (W/m2) 50.50 1367.6 0.037
Black-body temperature (K) 110.0 254.3 0.433
Moment of inertia (I/MR2) 0.254 0.3308 0.768
J2 (x 10-6) 14,736 1082.63 13.611
Jupiter Earth Ratio (Jupiter/Earth)
Semimajor axis (106 km) 778.57 149.60 5.204
Sidereal orbit period (days) 4,332.589 365.256 11.862
Tropical orbit period (days) 4,330.595 365.242 11.857
Perihelion (106 km) 740.52 147.09 5.034
Aphelion (106 km) 816.62 152.10 5.369
Synodic period (days) 398.88 - -
Mean orbital velocity (km/s) 13.07 29.78 0.439
Max. orbital velocity (km/s) 13.72 30.29 0.453
Min. orbital velocity (km/s) 12.44 29.29 0.425
Orbit inclination (deg) 1.304 0.000 -
Orbit eccentricity 0.0489 0.0167 2.928
Sidereal rotation period (hours) 9.9250* 23.9345 0.415
Length of day (hrs) 9.9259 24.0000 0.414
Obliquity to orbit (deg) 3.13 23.45 0.133
* System III (1965.0) coordinates
Discoverer: Unknown
Discovery Date: Prehistoric
Distance from Earth
Minimum (106 km) 588.5
Maximum (106 km) 968.1
Apparent diameter from Earth
Maximum (seconds of arc) 59.0
Minimum (seconds of arc) 29.8
Mean values at opposition from Earth
Distance from Earth (106 km) 628.76
Apparent diameter (seconds of arc) 46.9
Apparent visual magnitude -2.7
Semimajor axis (AU) 5.20336301 Orbital eccentricity 0.04839266 Orbital inclination (deg) 1.30530 Longitude of ascending node (deg) 100.55615 Longitude of perihelion (deg) 14.75385 Mean Longitude (deg) 34.40438
Dipole field strength: 4.28 gauss-Rj3
Dipole tilt to rotational axis: 9.6 degrees
Longitude of tilt: 201.7 degrees
Dipole offset (planet center to dipole center) distance: 0.131 Rj
Latitude/Longitude of offset vector: -8.0 degrees/148.57 degrees
Note: All latitudes/longitudes are given in Jovian System III (1965.0) coordinates.
Rj denotes Jovian radii, 71,398 km
Surface Pressure: >>100 bars
Average temperature: ~129 K
Temperature at 1 bar: ~165 K
Density at 1 bar: ~0.16 kg/m3
Wind speeds
Up to ~150 m/s (<30 degrees latitude)
Up to ~40 m/s (>30 degrees latitude)
Scale height: 27 km
Mean molecular weight: 2.22 g/mole
Atmospheric composition (uncertainty in parentheses)
Major: Molecular hydrogen (H2) - 89.8% (2.0%); Helium (He) - 10.2% (2.0%)
Minor (ppm): Methane (CH4) - 3000 (1000); Ammonia (NH3) - 260 (40);
Hydrogen Deuteride (HD) - 28 (10); Ethane (C2H6) - 5.8 (1.5);
Water (H2O) - ~4 (varies with pressure)
Aerosols: Ammonia ice, water ice, ammonia hydrosulfide
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