Fenrir (moon)

Fenrir
Discovery
Discovery site	Subaru, Gemini; Jan T. Kleyna; Brian G. Marsden
Designations
Designation	Saturn XLI
Pronunciation	/ˈfɛnrɪər/ or /ˈfɛnrər/
Named after	Fenris Wolf
Alternative names	S/2004 S 16
Adjectives	Fenrian /ˈfɛnriən/
Orbital characteristics
Semi-major axis	22,454,000 km
Eccentricity	0.1363
Orbital period	1260.35 d (3.45 yr)
Mean anomaly	146.614°
Inclination	164.955°
Longitude of ascending node	330.95°
Argument of perihelion	120.264°
Satellite of	Saturn
Group	Norse group
Physical characteristics
Mean diameter	4+50%; −30% km
Albedo	0.04 (assumed)
Apparent magnitude	25.0

Fenrir /ˈfɛnrɪər/, or Saturn XLI (provisional designation S/2004 S 16), is a natural satellite of Saturn. Its discovery was announced by Scott S. Sheppard, David C. Jewitt, Jan Kleyna, and Brian G. Marsden on May 4, 2005, from observations taken between December 13, 2004, and March 5, 2005. Fenrir has an apparent magnitude of 25,^[7] making it one of the faintest known moons in the Solar System, and was discovered using some of the largest telescopes in the world.^[1] It is even too dark^{[citation needed]} to be observed by the Cassini spacecraft in orbit around Saturn, for which it never gets brighter than approximately 17th apparent magnitude. Fenrir was named after Fenrisulfr, a giant wolf from Norse mythology, father of Hati and Skoll, son of Loki, destined to break its bonds for Ragnarök.

Fenrir is about 4 kilometres in diameter,^[7] and orbits Saturn at an average distance of 22,454 Mm in 1260 days, at an inclination of 163° to the ecliptic (143° to Saturn's equator) with an eccentricity of 0.136. The Fenrian orbit is retrograde: it orbits Saturn in a direction opposite to the planet's spin, suggesting that this irregular moon was captured by Saturn.^[8]

References[]

^ Jump up to: ^a ^b ^c ^d Daniel W. E. Green (2005-05-04). "IAUC 8523: NEW Sats OF SATURN". International Astronomical Union.
^ Daniel W. E. Green (2007-04-05). "IAUC 8826: Sats OF JUPITER, SATURN". International Astronomical Union.
^ "Fenrir". Dictionary.com Unabridged. Random House.
^ Merriam-Webster's Encyclopedia of Literature (1995)
^ The oblique stem of the name is Fenri, as in Fenrisulfr. The -r is the nominative case ending.
^ Jacobson, R.A. (2007) SAT270, SAT271 (2009-04-03). "Planetary Satellite Mean Orbital Parameters". JPL/NASA. Retrieved 2009-07-30.CS1 maint: multiple names: authors list (link)
^ Jump up to: ^a ^b ^c ^d Scott S. Sheppard. "Saturn's Known Satellites". Carnegie Institution (Department of Terrestrial Magnetism). Retrieved 2009-07-30.
^ David C. Jewitt. "Twelve New Moons for Saturn - 2005 May 03". University of Hawaii (Institute for Astronomy). Archived from the original on September 18, 2009. Retrieved 2009-07-30.

External links[]

Saturn's Known Satellites (by Scott S. Sheppard)
MPEC 2005-J13: Twelve New Satellites of Saturn May 3, 2005 (discovery and initial ephemeris)

[iauc8523-1] Jump up to: ^a ^b ^c ^d Daniel W. E. Green (2005-05-04). "IAUC 8523: NEW Sats OF SATURN". International Astronomical Union.

[iauc8826-2] Daniel W. E. Green (2007-04-05). "IAUC 8826: Sats OF JUPITER, SATURN". International Astronomical Union.

[3] "Fenrir". Dictionary.com Unabridged. Random House.

[4] Merriam-Webster's Encyclopedia of Literature (1995)

[5] The oblique stem of the name is Fenri, as in Fenrisulfr. The -r is the nominative case ending.

[jpl-6] Jacobson, R.A. (2007) SAT270, SAT271 (2009-04-03). "Planetary Satellite Mean Orbital Parameters". JPL/NASA. Retrieved 2009-07-30.CS1 maint: multiple names: authors list (link)

[sheppard-7] Jump up to: ^a ^b ^c ^d Scott S. Sheppard. "Saturn's Known Satellites". Carnegie Institution (Department of Terrestrial Magnetism). Retrieved 2009-07-30.

[jewitt-8] David C. Jewitt. "Twelve New Moons for Saturn - 2005 May 03". University of Hawaii (Institute for Astronomy). Archived from the original on September 18, 2009. Retrieved 2009-07-30.

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hide v t Moons of Saturn
Listed in approximately increasing distance from Saturn as of epoch JD 2459200.5.
Ring shepherds	S/2009 S 1 Ring moonlets Pan Daphnis Atlas Prometheus Pandora
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G Ring	Aegaeon
Alkyonides	Methone Anthe Pallene
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Outer large	Rhea Titan Hyperion Iapetus
Inuit group (7)	Kiviuq Ijiraq Paaliaq Saturn LX S/2004 S 31 Tarqeq Siarnaq
Norse group (46)	Phoebe Skathi S/2004 S 37 S/2007 S 2 Skoll Hyrrokkin Greip Mundilfari S/2004 S 13 (?) S/2006 S 1 S/2007 S 3 (?) Suttungr Saturn LIV Jarnsaxa Narvi Bergelmir Hati S/2004 S 17 (?) S/2004 S 12 (?) Saturn LIX Farbauti Thrymr Bestla S/2004 S 7 (?) Aegir Saturn LXI Saturn LV Saturn LVII Saturn LXII Saturn LVI S/2006 S 3 Saturn LXV Kari S/2004 S 28 Loge Saturn LXVI Fenrir Ymir Surtur Saturn LXIII S/2004 S 21 S/2004 S 39 S/2004 S 36 Fornjot Saturn LXIV Saturn LVIII
Gallic group (4)	Albiorix Bebhionn Erriapus Tarvos
Prograde outer satellites	S/2004 S 24
Rings of Saturn Cassini–Huygens Themis Chiron S/2004 S 6 S/2004 S 4 S/2004 S 3 In fiction

Discovery^[1]
Discovery site	Subaru, Gemini Jan T. Kleyna Brian G. Marsden
Designations
Designation	Saturn XLI
Pronunciation	/ˈfɛnrɪər/^[3] or /ˈfɛnrər/^[4]
Named after	Fenris Wolf
Alternative names	S/2004 S 16^[1]^[2]
Adjectives	Fenrian /ˈfɛnriən/^[5]
Orbital characteristics^[6]
Semi-major axis	22,454,000 km
Eccentricity	0.1363
Orbital period	1260.35 d (3.45 yr)
Mean anomaly	146.614°
Inclination	164.955°
Longitude of ascending node	330.95°
Argument of perihelion	120.264°
Satellite of	Saturn
Group	Norse group
Physical characteristics
Mean diameter	4+50% −30% km^[7]
Albedo	0.04 (assumed)^[1]
Apparent magnitude	25.0^[7]