Calypso (// kə-LIP-soh; Greek: Καλυψώ) is a moon of Saturn. It was discovered in 1980, from ground-based observations, by Dan Pascu, P. Kenneth Seidelmann, William A. Baum, and Douglas G. Currie, and was provisionally designated S/1980 S 25 (the 25th satellite of Saturn discovered in 1980). Several other apparitions of it were recorded in the following months: S/1980 S 29, S/1980 S 30, S/1980 S 32, and S/1981 S 2. In 1983 it was officially named after Calypso of Greek mythology.[a] It is also designated as Saturn XIV or Tethys C.
Calypso image from Cassini
(February 13, 2010)
|Discovery date||March 13, 1980|
|1.887802 d |
|Inclination||1.56° (to Saturn's equator)|
|Dimensions||30.2 × 23 × 14 km |
|10.7±0.7 km |
|Albedo||1.34±0.10 (geometric) |
Calypso is co-orbital with the moon Tethys, and resides in Tethys' trailing Lagrangian point (L5), 60 degrees behind Tethys. This relationship was first identified by Seidelmann et al. in 1981. The moon Telesto resides in the other (leading) Lagrangian point of Tethys, 60 degrees in the other direction from Tethys. Calypso and Telesto have been termed "Tethys trojans", by analogy to the trojan asteroids, and are half of the four presently known trojan moons.
Like many other small Saturnian moons and small asteroids, Calypso is irregularly shaped, has overlapping large craters, and appears to also have loose surface material capable of smoothing the craters' appearance. Its surface is one of the most reflective (at visual wavelengths) in the Solar System, with a visual geometric albedo of 1.34. This very high albedo is the result of the sandblasting of particles from Saturn's E-ring, a faint ring composed of small, water-ice particles generated by Enceladus' south polar geysers.
- Transactions of the International Astronomical Union, Vol. XVIIIA, 1982 (confirms Janus, names Epimetheus, Telesto, Calypso) (mentioned in IAUC 3872: Satellites of Jupiter and Saturn, September 30, 1983)
- Marsden, Brian G. (July 31, 1980). "Satellites of Saturn" (discovery). IAU Circular. 3496. Retrieved 2011-12-23.
- Marsden, Brian G. (December 11, 1980). "Satellites of Saturn". IAU Circular. 3549. Retrieved 2011-12-23.
- Marsden, Brian G. (April 16, 1981). "Satellites of Saturn". IAU Circular. 3593. Retrieved 2011-12-23.
- Marsden, Brian G. (May 18, 1981). "Satellites of Saturn". IAU Circular. 3605. Retrieved 2011-12-23.
- Marsden, Brian G. (September 30, 1983). "Satellites of Jupiter and Saturn". IAU Circular. 3872. Archived from the original on 2011-07-25. Retrieved 2011-12-23.
- Mason, Betsy (February 15, 2010). "New Close-Ups of Saturn's Moons Mimas and Calypso". wired.com. Condé Nast Digital. Retrieved 2011-12-23.
- Seidelmann, P. K.; Harrington, R. S.; Pascu, D.; Baum, W. A.; Currie, D. G.; Westphal, J. A.; Danielson, G. E. (1981). "Saturn satellite observations and orbits from the 1980 ring plane crossing". Icarus. 47 (2): 282. Bibcode:1981Icar...47..282S. doi:10.1016/0019-1035(81)90172-X.
- Thomas, P. C. (July 2010). "Sizes, shapes, and derived properties of the saturnian satellites after the Cassini nominal mission" (PDF). Icarus. 208 (1): 395–401. Bibcode:2010Icar..208..395T. doi:10.1016/j.icarus.2010.01.025.
- Verbiscer, A.; French, R.; Showalter, M.; Helfenstein, P. (9 February 2007). "Enceladus: Cosmic Graffiti Artist Caught in the Act". Science. 315 (5813): 815. Bibcode:2007Sci...315..815V. doi:10.1126/science.1134681. PMID 17289992. Retrieved 20 December 2011. (supporting online material, table S1)