Mundilfari (moon)

Mundilfari

Discovery images of Mundilfari (circled) taken by the CFHT in September 2000
Discovery
Discovered by	Gladman et al.
Discovery date	2000
Designations
Designation	Saturn XXV
Pronunciation	Icelandic: [ˈmʏntɪlvarɪ][a]
Named after	Mundilfari
Alternative names	S/2000 S 9
Orbital characteristics[1]
Semi-major axis	18590300 km
Eccentricity	0.210
Orbital period (sidereal)	−952.95 days
Inclination	168.4°
Satellite of	Saturn
Group	Norse group
Physical characteristics
Dimensions	11.78 × 7 × 5.86 km (modeled)[2]
Mean diameter	7+50% −30% km[3]
Synodic rotation period	6.74±0.08 hours[3]
Albedo	0.06 (assumed)[4]
Spectral type	P
Apparent magnitude	23.8[5][4]
Absolute magnitude (H)	14.5[4]

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 kilometres in diameter, and orbits Saturn at an average distance of 18,5903 Mm in 952.95 days, at an inclination of 168.4° to the ecliptic, in a retrograde direction and with an eccentricity of 0.210.^[1]

Mundilfari may have formed from debris knocked off Phoebe by large impacts at some point in the Solar System's history. 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.^[6] Its rotation period is 6.74±0.08 hours, the second-fastest among all the irregular moons studied by Cassini–Huygens after Hati,^[3] and it appears to be very elongated in shape.^[4]

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

Notes

1. The name is also found as Mundilföri ~ Mundilfœri. This would correspond to modern Icelandic Mundilfæri [ˈmʏntɪlvairɪ].

References

1. "Planetary Satellite Mean Elements". ssd.jpl.nasa.gov. Retrieved 2024-02-08.
2. Melnikov, A. V.; Kopylova, Yu. G. (2022-12-01). "Simulation of the Rotational Dynamics and Light Curves of Saturn's Small Moons in the Fast Rotation Mode". Solar System Research. 56 (6). Springer Link: 403–410. doi:10.1134/S0038094622050045. ISSN 1608-3423.
3. Denk, T.; Mottola, S. (2019). Cassini Observations of Saturn's Irregular Moons (PDF). 50th Lunar and Planetary Science Conference. Lunar and Planetary Institute.
4. Denk, Tilmann; Mottola, Stefano; Tosi, Frederico; Bottke, William F.; Hamilton, Douglas P. (2018). "The Irregular Satellites of Saturn". Enceladus and the Icy Moons of Saturn (PDF). Vol. 322. University of Arizona Press. pp. 409–434. Bibcode:2018eims.book..409D. doi:10.2458/azu_uapress_9780816537075-ch020. ISBN 9780816537488.
5. "Scott S. Sheppard - SaturnMoons".
6. Grav, T.; Bauer, J. (2007-03-08) [2006-11-18]. "A deeper look at the colors of the Saturnian irregular satellites". Icarus. 191 (1): 267–285. arXiv:astro-ph/0611590. Bibcode:2007Icar..191..267G. doi:10.1016/j.icarus.2007.04.020.

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)