Saturn

Saturn
Saturn and its prominent rings, as captured by the Cassini orbiter
Designations
Pronunciation/ˈsætərn/ [1]
Named after
Saturn
AdjectivesSaturnian /səˈtɜːrniən/,[2] Cronian[3] / Kronian[4] /ˈkrniən/[5]
Symbol♄
Orbital characteristics[6]
Epoch J2000.0
Aphelion1,514.50 million km (10.1238 AU)
Perihelion1,352.55 million km (9.0412 AU)
1,433.53 million km (9.5826 AU)
Eccentricity0.0565
378.09 days
9.68 km/s (6.01 mi/s)
317.020°[8]
Inclination
113.665°
2032-Nov-29[10]
339.392°[8]
Known satellites146 with formal designations; innumerable additional moonlets.[11][12]
Physical characteristics[6]
Mean radius
58,232 km (36,184 mi)[a]
9.1402 Earths
Equatorial radius
  • 60,268 km (37,449 mi)[a]
  • 9.449 Earths
Polar radius
  • 54,364 km (33,780 mi)[a]
  • 8.552 Earths
Flattening0.09796
Circumference365882.4 km (227348.8 mi) (equatorial)[13]
  • 4.27×1010 km2 (1.65×1010 sq mi)[14][a]
  • 83.703 Earths
Volume
  • 8.2713×1014 km3 (1.9844×1014 cu mi)[a]
  • 763.59 Earths
Mass
  • 5.6834×1026 kg
  • 95.159 Earths
Mean density
0.687 g/cm3 (0.0248 lb/cu in)[b]
0.1246 Earths
0.22[15]
35.5 km/s (22.1 mi/s)[a]
10 h 32 m 36 s;
10.5433 hours,[16] 10 h 39 m;
10.7 hours[7]
10h 33m 38s + 1m 52s
1m 19s
[17][18]
Equatorial rotation velocity
9.87 km/s (6.13 mi/s; 35,500 km/h)[a]
26.73° (to orbit)
North pole right ascension
40.589°; 2h 42m 21s
North pole declination
83.537°
Albedo
Surface temp. min mean max
1 bar 134 K
0.1 bar 88 K[21] 97 K[22] 151 K[21]
−0.55[23] to +1.17[23]
−9.7[24]
14.5″ to 20.1″ (excludes rings)
Atmosphere[6]
Surface pressure
140 kPa[25]
59.5 km (37.0 mi)
Composition by volume
  • 96.3%±2.4% hydrogen
  • 3.25%±2.4% helium
  • 0.45%±0.2% methane
  • 0.0125%±0.0075% ammonia
  • 0.0110%±0.0058% hydrogen deuteride
  • 0.0007%±0.00015% ethane
  • Icy volatiles:

Saturn is the sixth planet from the Sun and the second-largest in the Solar System, after Jupiter. It is a gas giant with an average radius of about nine-and-a-half times that of Earth.[26][27] It has only one-eighth the average density of Earth, but is over 95 times more massive.[28][29][30] Even though Saturn is nearly the size of Jupiter, Saturn has less than one-third of Jupiter's mass. Saturn orbits the Sun at a distance of 9.59 AU (1,434 million km) with an orbital period of 29.45 years.

Saturn's interior is thought to be composed of a rocky core, surrounded by a deep layer of metallic hydrogen, an intermediate layer of liquid hydrogen and liquid helium, and finally, a gaseous outer layer. Saturn has a pale yellow hue due to ammonia crystals in its upper atmosphere. An electrical current within the metallic hydrogen layer is thought to give rise to Saturn's planetary magnetic field, which is weaker than Earth's, but which has a magnetic moment 580 times that of Earth due to Saturn's larger size. Saturn's magnetic field strength is around one-twentieth of Jupiter's.[31] The outer atmosphere is generally bland and lacking in contrast, although long-lived features can appear. Wind speeds on Saturn can reach 1,800 kilometres per hour (1,100 miles per hour).

The planet has a bright and extensive ring system composed mainly of ice particles, with a smaller amount of rocky debris and dust. At least 146 moons[32] are known to orbit the planet, of which 63 are officially named; this does not include the hundreds of moonlets in its rings. Titan, Saturn's largest moon and the second largest in the Solar System, is larger (while less massive) than the planet Mercury and is the only moon in the Solar System to have a substantial atmosphere.[33]

  1. ^ Cite error: The named reference walter2003 was invoked but never defined (see the help page).
  2. ^ "Saturnian". Oxford English Dictionary (Online ed.). Oxford University Press. (Subscription or participating institution membership required.)
  3. ^ "Enabling Exploration with Small Radioisotope Power Systems" (PDF). NASA. September 2004. Archived from the original (PDF) on 22 December 2016. Retrieved 26 January 2016.
  4. ^ Müller; et al. (2010). "Azimuthal plasma flow in the Kronian magnetosphere". Journal of Geophysical Research. 115 (A8): A08203. Bibcode:2010JGRA..115.8203M. doi:10.1029/2009ja015122.
  5. ^ "Cronian". Oxford English Dictionary (Online ed.). Oxford University Press. (Subscription or participating institution membership required.)
  6. ^ a b c Cite error: The named reference fact was invoked but never defined (see the help page).
  7. ^ a b "Planetary Physical Parameters". NASA Jet Propulsion Laboratory.
  8. ^ a b c d Cite error: The named reference VSOP87 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Souami_Souchay_2012 was invoked but never defined (see the help page).
  10. ^ "HORIZONS Planet-center Batch call for November 2032 Perihelion". ssd.jpl.nasa.gov (Perihelion for Saturn's planet-center (699) occurs on 2032-Nov-29 at 9.0149170au during a rdot flip from negative to positive). NASA/JPL. Archived from the original on 7 September 2021. Retrieved 7 September 2021.
  11. ^ Cite error: The named reference JPLmoons was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference UBC-20230511 was invoked but never defined (see the help page).
  13. ^ "By the Numbers – Saturn". NASA Solar System Exploration. NASA. Archived from the original on 10 May 2018. Retrieved 5 August 2020.
  14. ^ Cite error: The named reference nasafact was invoked but never defined (see the help page).
  15. ^ Fortney, J.J.; Helled, R.; Nettlemann, N.; Stevenson, D.J.; Marley, M.S.; Hubbard, W.B.; Iess, L. (6 December 2018). "The Interior of Saturn". In Baines, K.H.; Flasar, F.M.; Krupp, N.; Stallard, T. (eds.). Saturn in the 21st Century. Cambridge University Press. pp. 44–68. ISBN 978-1-108-68393-7. Archived from the original on 2 May 2020. Retrieved 23 July 2019.
  16. ^ Cite error: The named reference CSeligman was invoked but never defined (see the help page).
  17. ^ McCartney, Gretchen; Wendel, JoAnna (18 January 2019). "Scientists Finally Know What Time It Is on Saturn". NASA. Archived from the original on 29 August 2019. Retrieved 18 January 2019.
  18. ^ Mankovich, Christopher; et al. (17 January 2019). "Cassini Ring Seismology as a Probe of Saturn's Interior. I. Rigid Rotation". The Astrophysical Journal. 871 (1): 1. arXiv:1805.10286. Bibcode:2019ApJ...871....1M. doi:10.3847/1538-4357/aaf798. S2CID 67840660.
  19. ^ Cite error: The named reference Hanel_et_al was invoked but never defined (see the help page).
  20. ^ Cite error: The named reference Mallama_et_al was invoked but never defined (see the help page).
  21. ^ a b "Saturn's Temperature Ranges". Sciencing. Archived from the original on 26 May 2021. Retrieved 26 May 2021.
  22. ^ "The Planet Saturn". National Weather Service. Archived from the original on 26 May 2021. Retrieved 26 May 2021.
  23. ^ a b Cite error: The named reference Mallama_and_Hilton was invoked but never defined (see the help page).
  24. ^ "Encyclopedia - the brightest bodies". IMCCE. Retrieved 29 May 2023.
  25. ^ Knecht, Robin (24 October 2005). "On The Atmospheres Of Different Planets" (PDF). Archived from the original (PDF) on 14 October 2017. Retrieved 14 October 2017.
  26. ^ Brainerd, Jerome James (24 November 2004). "Characteristics of Saturn". The Astrophysics Spectator. Archived from the original on 1 October 2011. Retrieved 5 July 2010.
  27. ^ "General Information About Saturn". Scienceray. 28 July 2011. Archived from the original on 7 October 2011. Retrieved 17 August 2011.
  28. ^ Brainerd, Jerome James (6 October 2004). "Solar System Planets Compared to Earth". The Astrophysics Spectator. Archived from the original on 1 October 2011. Retrieved 5 July 2010.
  29. ^ Dunbar, Brian (29 November 2007). "NASA – Saturn". NASA. Archived from the original on 29 September 2011. Retrieved 21 July 2011.
  30. ^ Cite error: The named reference Mass ref 3 was invoked but never defined (see the help page).
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  32. ^ "MPEC 2023-J49 : S/2006 S 12". Minor Planet Electronic Circulars. Minor Planet Center. 7 May 2023. Retrieved 7 May 2023.
  33. ^ Munsell, Kirk (6 April 2005). "The Story of Saturn". NASA Jet Propulsion Laboratory; California Institute of Technology. Archived from the original on 16 August 2008. Retrieved 7 July 2007.


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