Tarvos (moon)


Tarvos discovery.gif
Animation of discovery images taken by the CFHT in September 2000
Discovered byB. J. Gladman et al.[1]
Discovery dateSeptember 23, 2000
Saturn XXI
Named after
Tarvos Trigaranus
S/2000 S 4
Orbital characteristics[4]
Epoch 2000 Feb. 26.00
17.983 Gm
926.2 d
(2.63 yr)
Satellite ofSaturn
GroupGallic group
Physical characteristics
Mean diameter
10.691±0.001 h[5]
Albedo0.04[6] assumed
Spectral type
light red
B−V=0.0.77, R−V=0.57[7]

Tarvos /ˈtɑːrvɒs/, 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.[8]


Discovery images of Tarvos (circled) taken by the CFHT

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 a high orbital eccentricity of 0.53.[4]

It is a member of the Gallic group of irregular satellites.


With a similar orbit and displaying a similar light-red colour, Tarvos is thought to have its origin in the break-up of a common progenitor[7][9] or to be a fragment of Albiorix.[10]


  1. ^ 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)
  2. ^ Discovery Circumstances (JPL)
  3. ^ Per the diminutive Tarvillus in Daniel Davis (2001) The Development of Celtic Linguistics, 1850-1900, p. 162
  4. ^ a b c Jacobson, R.A. (2007) SAT270, SAT271 (2007-06-28). "Planetary Satellite Mean Orbital Parameters". JPL/NASA. Retrieved 2008-01-19.CS1 maint: multiple names: authors list (link)
  5. ^ a b Denk, T.; Mottola, S. (2019). Cassini Observations of Saturn's Irregular Moons (PDF). 50th Lunar and Planetary Science Conference. Lunar and Planetary Institute.
  6. ^ Scott Sheppard. "Saturn's Known Satellites". Department of Terrestrial Magnetism. Retrieved 2007-03-06.
  7. ^ a b Grav, Tommy; Holman, Matthew J.; Gladman, Brett J.; Aksnes, Kaare; Photometric survey of the irregular satellites, Icarus, 166 (2003), pp. 33–45
  8. ^ IAUC 8177: Satellites of Jupiter, Saturn, Uranus August 8, 2003 (naming the moon)
  9. ^ 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
  10. ^ Grav, Tommy; and Bauer, J.; A deeper look at the colors of Saturnian irregular satellites
  • Ephemeris IAU-MPC NSES

External links