Mundilfari (moon)

Mundilfari, or Saturn XXV, is a natural satellite of Saturn. It was discovered by Brett J. Gladman, et al. in 2000, and given the temporary designation S/2000 S 9. Mundilfari is about 7 kilometers in diameter, and orbits Saturn at an average distance of 18,5903 Mm in 952.95 days, an averaged eccentricity of 0.210,<ref name="JPLmeanelements">Template:Cite web</ref> and at an inclination of 168.4° to the ecliptic in a retrograde sense (compared to Saturn's orbit around the Sun).

Mundilfari may have formed from debris knocked off Phoebe by large impacts at some point in the Solar System's history, but it is on an orbit sufficiently different from Phoebe that this may be difficult to reconcile. With a spectral slope of −5.0%/100, Mundilfari is the bluest of all the moons studied by Grav and Bauer (2007), slightly more so than Phoebe (−2.5%/100 nm) and about as blue as Erriapus (+5.1%/100 nm) is red.<ref name="Grav2006">Template:Cite journal</ref> Its rotation period is Template:Val hours, the second-fastest among all the irregular moons studied by Cassini–Huygens after Hati,<ref name="LPSC2654">Template:Cite conference</ref> and it appears to be very elongated in shape.<ref name="Denk2018">Template:Cite book</ref>

It was named in August 2003 from Norse mythology, where Mundilfari is the father of the goddess Sól (Sun) and the god Máni (Moon).

Mundilfari is the largest remaining fragment of an eponymous sub-group of small retrograde irregular moons, which belongs to the Norse group.<ref name="Ashton2025a">Template:Cite arXiv</ref><ref name="Ashton2025b">Template:Cite journal</ref>

Notes

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External links

• IAUC 7538: S/2000 S 7, S/2000 S 8, S/2000 S 9 December 7, 2000 (discovery)
• MPEC 2000-Y15: S/2000 S 1, S/2000 S 2, S/2000 S 7, S/2000 S 8, S/2000 S 9 December 19, 2000 (discovery and ephemeris)
• IAUC 8177: Satellites of Jupiter, Saturn, Uranus August 8, 2003 (naming the moon)
• https://phas.ubc.ca/2025-discovery-more-saturnian-moons March 11, 2025