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, and at an inclination of 168.4° to the ecliptic in a retrograde sense.
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, slightly more so than Phoebe and about as blue as Erriapus is red. Its rotation period is hours, the second-fastest among all the irregular moons studied by Cassini–Huygens after Hati, and it appears to be very elongated in shape.
It was named in August 2003 from Norse mythology, where Mundilfari is the father of the goddess Sól and the god Máni.
Mundilfari is the largest remaining fragment of an eponymous sub-group of small retrograde irregular moons, which belongs to the Norse group.