Jupiter Fact Sheet


[Montage of Jupiter and the Galilean Satellites]

Jupiter/Earth Comparison


Bulk parameters

                                   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    

Orbital parameters

                                   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


Jupiter Observational Parameters

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      

Jupiter Mean Orbital Elements (J2000)

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  

Jovian Magnetosphere

Goddard Space Flight Center O4 Model
    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


Jovian Atmosphere

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

Questions and comments about this page should be addressed to:
Dr. David R. Williams, dwilliam@nssdc.gsfc.nasa.gov, +1-301-286-1258
NSSDC, Mail Code 633, NASA/Goddard Space Flight Center, Greenbelt, MD 20771
or
Dr. Edwin V. Bell II, ed.bell@gsfc.nasa.gov, +1-301-286-1187
NSSDC, Mail Code 633, NASA/Goddard Space Flight Center, Greenbelt, MD 20771
[NSSDC logo]

NASA Official: J. H. King, joseph.h.king@gsfc.nasa.gov
Last Updated: 14 July 2000, DRW