Fenrir (moon)

Fenrir
Discovery[1]
Discovered by	Scott S. Sheppard, David C. Jewitt, Jan Kleyna
Discovery site	Subaru, Gemini, Keck
Discovery date	2004
Designations
Designation	Saturn XLI
Pronunciation	/ˈfɛnrɪər/[2] or /ˈfɛnrər/[3]
Named after	Fenris Wolf
Alternative names	S/2004 S 16[1][4]
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]

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 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

Daniel W. E. Green (2005-05-04). "IAUC 8523: NEW Sats OF SATURN". International Astronomical Union.
"Fenrir". Dictionary.com Unabridged. Random House.
Merriam-Webster's Encyclopedia of Literature (1995)
Daniel W. E. Green (2007-04-05). "IAUC 8826: Sats OF JUPITER, SATURN". International Astronomical Union.
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)
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)

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[iauc8523-1] Daniel W. E. Green (2005-05-04). "IAUC 8523: NEW Sats OF SATURN". International Astronomical Union.

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

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

[iauc8826-4] Daniel W. E. Green (2007-04-05). "IAUC 8826: Sats OF JUPITER, SATURN". International Astronomical Union.

[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] 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.

Saturn
Outline of Saturn
Geography	Dragon Storm Great White Spot Hexagon Magnetosphere Rings
Moons	S/2009 S 1 Ring moonlets Pan Daphnis Atlas Prometheus S/2004 S 6 S/2004 S 4 S/2004 S 3 Pandora Epimetheus Janus Aegaeon Mimas Methone Anthe Pallene Enceladus Tethys Telesto Calypso Dione Helene Polydeuces Rhea Titan Hyperion Iapetus Kiviuq Ijiraq Phoebe Paaliaq Skathi S/2004 S 37 Albiorix S/2007 S 2 S/2004 S 29 Bebhionn Erriapus Skoll S/2004 S 31 Siarnaq Tarqeq S/2004 S 13 Greip Hyrrokkin Jarnsaxa Tarvos Mundilfari S/2006 S 1 S/2004 S 17 Bergelmir Narvi S/2004 S 20 Suttungr Hati S/2004 S 12 S/2004 S 27 Farbauti Thrymr S/2004 S 30 Aegir S/2007 S 3 Bestla S/2004 S 7 S/2004 S 22 S/2004 S 23 S/2004 S 25 S/2004 S 32 S/2006 S 3 S/2004 S 38 Fenrir S/2004 S 28 Surtur Kari S/2004 S 35 Ymir S/2004 S 21 S/2004 S 24 Loge S/2004 S 36 S/2004 S 39 S/2004 S 33 S/2004 S 34 Fornjot S/2004 S 26
Astronomy	Delta Octantis Saturn-crossing minor planets
Exploration	Cassini–Huygens (Huygens) timeline retirement Pioneer 11 Voyager program Voyager 1 Voyager 2
Related	Fiction Moons The Day the Earth Smiled In Saturn's Rings (2018 documentary)

Natural satellites of the Solar System
Planetary satellites	Terrestrial Martian Jovian Saturnian Uranian Neptunian
Dwarf-planet satellites	Plutonian Haumean Makemakean Eridian Gonggong Quaoar Orcus
Minor-planet moons	Main belt binaries: Antiope Frostia Berna Tokai Ostro Balam Doppler Pauling Iwamoto Wolff Bettig Christophedumas Trojans: Patroclus–Menoetius Hektor–Skamandrios Iphthime Eurydamas TNOs: Huya Typhon–Echidna Lempo–Paha–Hiisi 2002 UX₂₅ Logos–Zoe Ceto–Phorcys Borasisi–Pabu Sila–Nunam Teharonhiawako–Sawiskera Salacia–Actaea 2002 WC₁₉ Altjira Varda–Ilmarë 2003 AZ₈₄ Gǃkúnǁʼhòmdímà–Gǃòʼé ǃHú Mors–Somnus Manwë–Thorondor ǂKá̦gára–ǃHãunu 2013 FY27
Ranked by size	Planetary-mass moon Ganymede largest: 5268 km / 0.413 Earths Titan Callisto Io Moon Europa Triton Titania Rhea Oberon Iapetus Charon Umbriel Ariel Dione Tethys Dysnomia Enceladus Miranda Vanth Proteus Mimas Ilmarë Nereid Hiʻiaka Actaea Hyperion ...
Discovery timeline Inner moons Irregular moons List Planetary-mass moons Naming Subsatellite Regular moons Trojan moons

Moons of Saturn
Listed in approximately increasing distance from Saturn.
Ring shepherds	S/2009 S 1 Ring moonlets Pan Daphnis Atlas Prometheus Pandora
Co-orbitals	Epimetheus Janus
G Ring	Aegaeon
Alkyonides	Methone Anthe Pallene
Inner large (with trojans)	Mimas Enceladus Tethys Telesto Calypso Dione Helene Polydeuces
Outer large	Rhea Titan Hyperion Iapetus
Inuit group	Kiviuq Ijiraq Paaliaq S/2004 S 29 S/2004 S 31 Siarnaq Tarqeq
Norse group	Phoebe Skathi S/2004 S 37 S/2007 S 2 Skoll S/2004 S 13 (?) Greip Hyrrokkin Jarnsaxa Mundilfari S/2006 S 1 S/2004 S 17 (?) Bergelmir Narvi S/2004 S 20 Suttungr Hati S/2004 S 12 (?) S/2004 S 27 Farbauti Thrymr S/2004 S 30 Aegir S/2007 S 3 (?) Bestla S/2004 S 7 (?) S/2004 S 22 S/2004 S 23 S/2004 S 25 S/2004 S 32 S/2006 S 3 S/2004 S 38 Fenrir S/2004 S 28 Surtur Kari S/2004 S 35 Ymir S/2004 S 21 Loge S/2004 S 36 S/2004 S 39 S/2004 S 33 S/2004 S 34 Fornjot S/2004 S 26
Gallic group	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