Tarvos (pronounced /ˈtɑrvɵs/ TAR-vəs), or Saturn XXI, is a prograde irregular satellite of Saturn. It was discovered by John J. Kavelaars, et al. on September 23, 2000 and given the temporary designation S/2000 S 4. The name, given in August 2003, is after Tarvos, a deity depicted as a bull god carrying three cranes alongside its back from Gaulish mythology.
Tarvos orbits Saturn at an average distance of 18 million km in 926 days and is about 15 km in diameter (assuming an albedo of 0.04). It has the most eccentric orbit around Saturn.
It is a member of the Gallic group of irregular satellites.
Sharing similar orbit and displaying similar light-red colour, Tarvos is thought to have its origin in a break-up of a common progenitor  or to be a fragment of Albiorix.
1. ^ Discovery Circumstances (JPL)
2. ^ IAUC 7513: S/2000 S 3 and S/2000 S 4 October 25, 2000 (discovery)
3. ^ MPEC 2000-Y14: S/2000 S 3, S/2000 S 4, S/2000 S 5, S/2000 S 6, S/2000 S 10 December 19, 2000 (discovery and ephemeris)
4. ^ a b c Jacobson, R.A. (2007) SAT270, SAT271 (2007-06-28). "Planetary Satellite Mean Orbital Parameters". JPL/NASA. http://ssd.jpl.nasa.gov/?sat_elem#saturn. Retrieved 2008-01-19.
5. ^ a b Scott Sheppard. "Saturn's Known Satellites". Department of Terrestrial Magnetism. http://www.dtm.ciw.edu/users/sheppard/satellites/satsatdata.html. Retrieved 2007-03-06.
6. ^ a b Grav, Tommy; Holman, Matthew J.; Gladman, Brett J.; Aksnes, Kaare; Photometric survey of the irregular satellites, Icarus, 166 (2003), pp. 33-45
7. ^ IAUC 8177: Satellites of Jupiter, Saturn, Uranus August 8, 2003 (naming the moon)
8. ^ Gladman, B. J.; Nicholson, P. D.; Burns, J. A.; Kavelaars, J. J.; Marsden, B. G.; Holman, M. J.; Grav, T.; Hergenrother, C. W.; Petit, J.-M.; Jacobson, R. A.; and Gray, W. J.; Discovery of 12 satellites of Saturn exhibiting orbital clustering, Nature, 412 (July 12, 2001), pp. 163–166
9. ^ Grav, Tommy; and Bauer, J.; A deeper look at the colors of Saturnian irregular satellites
* Ephemeris IAU-MPC NSES
* David Jewitt pages
* Saturn's Known Satellites (by Scott S. Sheppard)