Saturn Fact Sheet


Saturn

Saturn/Earth Comparison


Bulk parameters

   
   Saturn   
 
   Earth   
Ratio
(Saturn/Earth)
Mass (1024 kg) 568.32 5.9722 95.16
Volume (1010 km3) 82,713 108.321 763.59
Equatorial radius (1 bar level) (km) 60,268 6,378.1 9.449
Polar radius (1 bar level) (km) 54,364 6,356.8 8.552
Volumetric mean radius (km) 58,232 6,371.0 9.140
Ellipticity (Flattening) 0.09796 0.00335 29.24
Mean density (kg/m3) 687 5,513 0.125
Gravity (mean, 1 bar) (m/s2) 11.19 9.82 1.140
Acceleration (eq., 1 bar) (m/s2) 8.96 9.78 0.916
Acceleration (pole, 1 bar) (m/s2) 12.14 9.83 1.235
Escape velocity (km/s) 35.5 11.19 3.172
GM (x 106 km3/s2) 37.931 0.39860 95.16
Bond albedo 0.342 0.294 1.16
Geometric albedo 0.499 0.434 1.15
V-band magnitude V(1,0) -8.91 -3.99 -
Solar irradiance (W/m2) 14.82 1,361.0 0.011
Black-body temperature (K) 81.0 254.0 0.319
Moment of inertia (I/MR2) 0.210 0.3308 0.635
J2 (x 10-6) 16,298. 1082.63 15.054
Number of natural satellites 146 1  
Planetary ring system Yes No  

Orbital parameters

   
   Saturn   
 
   Earth   
Ratio
(Saturn/Earth)
Semimajor axis (106 km) 1,432.041 149.598 9.573
Sidereal orbit period (days) 10,759.22 365.256 29.457
Tropical orbit period (days) 10,746.94 365.242 29.424
Perihelion (106 km) 1,357.554 147.095 9.229
Aphelion (106 km) 1,506.527 152.100 9.905
Synodic period (days) 378.09 - -
Mean orbital velocity (km/s) 9.67 29.78 0.325
Max. orbital velocity (km/s) 10.14 30.29 0.335
Min. orbital velocity (km/s) 9.14 29.29 0.312
Orbit inclination (deg) 2.486 0.000 -
Orbit eccentricity 0.0520 0.0167 3.114
Sidereal rotation period (hrs) 10.656* 23.9345 0.445
Length of day (hrs) 10.656 24.0000 0.444
Obliquity to orbit (deg) 26.73 23.44 1.140

* Saturnian System III coordinates


Saturn Observational Parameters

Discoverer:      Unknown
Discovery Date:  Prehistoric

Distance from Earth
        Minimum (106 km)         1205.5
        Maximum (106 km)         1658.6
Apparent diameter from Earth
        Maximum (seconds of arc)   19.9
        Minimum (seconds of arc)   14.5
Mean values at opposition from Earth
        Distance from Earth (106 km)       1277.13    
        Apparent diameter (seconds of arc)   18.8
        Apparent visual magnitude             0.7 
Maximum apparent visual magnitude             0.43  

Mean values at opposition including rings
        Apparent visual magnitude             0.05 
Maximum apparent visual magnitude            -0.55     
   

Saturn Mean Orbital Elements (J2000)

Semimajor axis (AU)                  9.53707032  
Orbital eccentricity                 0.05415060   
Orbital inclination (deg)            2.48446   
Longitude of ascending node (deg)  113.71504   
Longitude of perihelion (deg)       92.43194   
Mean Longitude (deg)                49.94432

North Pole of Rotation

Right Ascension: 40.589 - 0.036T
Declination    : 83.537 - 0.004T
Reference Date : 12:00 UT 1 Jan 2000 (JD 2451545.0)
T = Julian centuries from reference date 

Saturnian Magnetosphere

Model GSFC-Z3
Dipole field strength: 0.215 Gauss-Rs3
Dipole tilt to rotational axis: 0.0
Dipole offset: 0.038 Rs 
Surface (1 Rs) field strength: 0.18 - 0.84 Gauss

Saturn's magnetic field has significant quadrapole and octapole moments,
making approximation of the central field as an offset dipole difficult.
Rs denotes Saturnian model radius, defined here to be 60,330 km


Saturnian Atmosphere

Surface Pressure: >>1000 bars  
Temperature at 1 bar: 134 K (-139 C)
Temperature at 0.1 bar: 84 K (-189 C)
Density at 1 bar: 0.19 kg/m3
Wind speeds
   Up to 400 m/s (<30 degrees latitude)
   Up to 150 m/s (>30 degrees latitude)
Scale height: 59.5 km
Mean molecular weight: 2.07 
Atmospheric composition (by volume, uncertainty in parentheses)
    Major:       Molecular hydrogen (H2) - 96.3% (2.4%); Helium (He) - 3.25% (2.4%)
    Minor (ppm): Methane (CH4) - 4500 (2000); Ammonia
(NH3) - 125 (75);
                 Hydrogen Deuteride (HD) - 110 (58); Ethane
(C2H6) - 7 (1.5)
    Aerosols:    Ammonia ice, water ice, ammonia hydrosulfide

Notes on the factsheets - definitions of parameters, units, notes on sub- and superscripts, etc.
Saturnian Satellite Fact Sheet
Saturnian Rings Fact Sheet

Planetary Fact Table - metric units
Planetary Fact Table - U.S. units
Planetary Fact Table - Earth ratio

Saturn Home Page
Directory to other Planetary Fact Sheets


NASA
Author/Curator:
Dr. David R. Williams, dave.williams@nasa.gov
NSSDCA, Mail Code 690.1
NASA Goddard Space Flight Center
Greenbelt, MD 20771
+1-301-286-1258


NASA Official: Dave Williams, david.r.williams@nasa.gov
Last Updated: 11 January 2024, DRW