Fenrir (moon)

Fenrir (/ˈfɛnrɪər/ FEN-reer) 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,^[4] 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 where it never gets brighter than ~17th 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,^[4] 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.^[5]

References

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)

Saturn
Geography	Dragon Storm Great White Spot Hexagon Magnetosphere Rings Diamonds
Moons	S/2009 S 1 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 Albiorix S/2007 S 2 Bebhionn Erriapus Skoll Siarnaq Tarqeq S/2004 S 13 Greip Hyrrokkin Jarnsaxa Tarvos Mundilfari S/2006 S 1 S/2004 S 17 Bergelmir Narvi Suttungr Hati S/2004 S 12 Farbauti Thrymr Aegir S/2007 S 3 Bestla S/2004 S 7 S/2006 S 3 Fenrir Surtur Kari Ymir Loge Fornjot
Astronomy	Delta Octantis Saturn-crossing minor planets
Exploration	Cassini–Huygens Enceladus Explorer Pioneer 11 Voyager program
Related	Fiction Saturn Moons

Natural satellites of the Solar System
Planetary satellites	Terrestrial Martian Jovian Saturnian Uranian Neptunian
Other satellites	Asteroid moons Plutonian Haumean Eridian Makemakean
Largest satellites (mean radius ≥ 100 km)	size Ganymede largest / 2634 km / 0.413 Earths Titan Callisto Io Moon Europa Triton Titania Rhea Oberon Iapetus Charon Umbriel Ariel Dione Tethys [Dysnomia] Enceladus Miranda Proteus Mimas [Hi'iaka] Nereid Hyperion Phoebe smallest / 106 km / 0.017 Earths abc's Ariel Callisto Charon Dione [Dysnomia] Enceladus Europa Ganymede [Hi'iaka] Hyperion Iapetus Io Mimas Miranda Moon Nereid Oberon Phoebe Proteus Rhea Tethys Titan Titania Triton Umbriel
Discovery timeline Inner moons Irregular moons List Naming Regular moons Trojan moons NOTE: Italicized moons are not close to being in hydrostatic equilibrium; [bracketed] moons may or may not be close to being in hydrostatic equilibrium.