Saturn Fact Sheet
![[Voyager 2 image of Saturn]](http://nssdc.gsfc.nasa.gov/planetary/image/saturn_voy2.jpg)
Saturn/Earth Comparison
Bulk parameters
Saturn Earth Ratio (Saturn/Earth)
Mass (1024 kg) 568.46 5.9736 95.159
Volume (1010 km3) 82,713 108.321 763.59
Radius (1 bar level) (km)
Equatorial 60,268 6,378.1 9.449
Polar 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 5,515 0.125
Gravity (eq., 1 bar) (m/s2) 10.44 9.80 1.065
Acceleration (eq., 1 bar) (m/s2) 8.96 9.78 0.916
Escape velocity (km/s) 35.5 11.19 3.172
GM (x 106 km3/s2) 37.931 0.3986 95.16
Bond albedo 0.342 0.306 1.12
Visual geometric albedo 0.47 0.367 1.28
Visual magnitude V(1,0) -8.88 -3.86 -
Solar irradiance (W/m2) 14.90 1,367.6 0.011
Black-body temperature (K) 81.1 254.3 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 56 1
Planetary ring system Yes No
Orbital parameters
Saturn Earth Ratio (Saturn/Earth)
Semimajor axis (106 km) 1,433.53 149.60 9.582
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) 1,352.55 147.09 9.195
Aphelion (106 km) 1,514.50 152.10 9.957
Synodic period (days) 378.09 - -
Mean orbital velocity (km/s) 9.69 29.78 0.325
Max. orbital velocity (km/s) 10.18 30.29 0.336
Min. orbital velocity (km/s) 9.09 29.29 0.310
Orbit inclination (deg) 2.485 0.000 -
Orbit eccentricity 0.0565 0.0167 3.383
Sidereal rotation period (hours) 10.656* 23.9345 0.445
Length of day (hrs) 10.656 24.0000 0.444
Obliquity to orbit (deg) 26.73 23.45 1.140
* Saturnian System III coordinates
Saturn Observational Parameters
Discoverer: Unknown
Discovery Date: Prehistoric
Distance from Earth
Minimum (106 km) 1195.5
Maximum (106 km) 1658.5
Apparent diameter from Earth
Maximum (seconds of arc) 20.1
Minimum (seconds of arc) 14.5
Mean values at opposition from Earth
Distance from Earth (106 km) 1277.42
Apparent diameter (seconds of arc) 19.5
Apparent visual magnitude 0.7
Maximum apparent visual magnitude 0.43
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: 40.5954 - 0.0577T
Declination : 83.5380 - 0.0066T
Reference Date : 12:00 UT 1 Jan 2000 (JD 2451545.0)
T = Julian centuries from reference date
Saturnian Magnetosphere
Dipole field strength: 0.210 gauss-Rs3
Dipole tilt to rotational axis: < 1 degree
Dipole offset (planet center to dipole center) distance: 0.04 to 0.05 Rs northward
Note: Saturn's magnetic field has significant quadrapole and octapole moments, making approximation of the central field as an offset dipole difficult.
Rs denotes Saturnian radii, 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 g/mole
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
http://nssdc.gsfc.nasa.gov/planetary/factsheet/saturnfact.html
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