Info

saturn

Saturn
Designations
Pronunciation /ˈsætərn/[1]
Adjectives Saturnian, Cronian
Orbital characteristics[2]
Epoch J2000.0
Aphelion 10.086 AU
(1,509 Gm)
Perihelion 9.024 AU
(1,350 Gm)
Semi-major axis
9.554909 AU
(1,429.39 Gm)[2]
Eccentricity 0.05555
Orbital period
  • 29.4571 yr
  • 10,759.22 d
  • 24,491.07 Saturnian solar days[3]
Synodic period
378.09 days[4]
Average orbital speed
9.69 km/s[4]
Mean anomaly
317.020°
Inclination
  • 2.485240° to ecliptic
  • 5.51° to Sun's equator
  • 0.93° to invariable plane[5]
Longitude of ascending node
113.665°
Argument of perihelion
339.392°
Known satellites 62 with formal designations; innumerable additional moonlets.[4]
Physical characteristics
Mean radius
58,232±6 km[6][a]
Equatorial radius
  • 60,268±4 km[6][a]
  • 9.4492 Earths
Polar radius
  • 54,364±10 km[6][a]
  • 8.5521 Earths
Flattening 0.09796±0.00018
Surface area
  • 4.27×1010 km2[a][7]
  • 83.703 Earths
Volume
  • 8.2713×1014 km3[4][a]
  • 763.59 Earths
Mass
  • 5.6836×1026 kg[4]
  • 95.159 Earths
Mean density
0.687 g/cm3[4][a]
(less than water)
Surface gravity
  • 10.44 m/s²[4][a]
  • 1.065 g
Moment of inertia factor
0.210[8]
Escape velocity
35.5 km/s[4][a]
Sidereal rotation period
10.55 hours[9]
(10 hr 33 min)
Equatorial rotation velocity
  • 9.87 km/s[a]
  • 35,500 km/h
Axial tilt
26.73° (to orbit)[4]
North pole right ascension
  • 2h 42m 21s
  • 40.589°[6]
North pole declination
83.537°[6]
Albedo
  • 0.342 (Bond)
  • 0.47 (geometric)[4]
Surface temp.minmeanmax
1 bar level   134 K (−139°C)[4]  
0.1 bar   84 K[4]  
Apparent magnitude
+1.47 to −0.24[10]
Angular diameter
14.5″ to 20.1″[4]
(excludes rings)
Atmosphere[4]
Scale height
59.5 km
Composition by volume

by volume:

≈ 96% hydrogen (H2)
≈ 3% helium (He)
≈ 0.4% methane (CH4)
≈ 0.01% ammonia (NH3)
≈ 0.01% hydrogen deuteride (HD)
0.0007% ethane (C2H6)
Ices:
  • ammonia (NH3)
  • water (H2O)
  • ammonium hydrosulfide (NH4SH)