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Calypso (moon)
Encyclopedia
Calypso 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
(the 25th satellite of Saturn discovered in 1980). Several other apparitions of it were recorded in the following months: , , , and . In 1983 it was officially named after Calypso
of Greek mythology
. It is also designated as or Tethys C.
Calypso is co-orbital with the moon Tethys
, and resides in Tethys' trailing Lagrangian point
, 60 degrees behind Tethys. This relationship was first identified by Seidelmann et al. in 1981. The moon Telesto
also 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 asteroid
s, 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.
Natural satellite
A natural satellite or moon is a celestial body that orbits a planet or smaller body, which is called its primary. The two terms are used synonymously for non-artificial satellites of planets, of dwarf planets, and of minor planets....
of Saturn
Saturn
Saturn is the sixth planet from the Sun and the second largest planet in the Solar System, after Jupiter. Saturn is named after the Roman god Saturn, equated to the Greek Cronus , the Babylonian Ninurta and the Hindu Shani. Saturn's astronomical symbol represents the Roman god's sickle.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
Provisional designation in astronomy
Provisional designation in astronomy is the naming convention applied to astronomical objects immediately following their discovery. The provisional designation is usually superseded by a permanent designation once a reliable orbit has been calculated...
(the 25th satellite of Saturn discovered in 1980). Several other apparitions of it were recorded in the following months: , , , and . In 1983 it was officially named after Calypso
Calypso (mythology)
Calypso was a nymph in Greek mythology, who lived on the island of Ogygia, where she detained Odysseus for a number of years. She is generally said to be the daughter of the Titan Atlas....
of Greek mythology
Greek mythology
Greek mythology is the body of myths and legends belonging to the ancient Greeks, concerning their gods and heroes, the nature of the world, and the origins and significance of their own cult and ritual practices. They were a part of religion in ancient Greece...
. It is also designated as or Tethys C.
Calypso is co-orbital with the moon Tethys
Tethys (moon)
Tethys or Saturn III is a mid-sized moon of Saturn about across. It was discovered by G. D. Cassini in 1684 and is named after titan Tethys of Greek mythology. Tethys is pronounced |Odysseus]] is about 400 km in diameter, while the largest graben—Ithaca Chasma is about 100 km wide and...
, and resides in Tethys' trailing Lagrangian point
Lagrangian point
The Lagrangian points are the five positions in an orbital configuration where a small object affected only by gravity can theoretically be stationary relative to two larger objects...
, 60 degrees behind Tethys. This relationship was first identified by Seidelmann et al. in 1981. The moon Telesto
Telesto (moon)
Telesto is a moon of Saturn. It was discovered by Smith, Reitsema, Larson and Fountain in 1980 from ground-based observations, and was provisionally designated '. In the following months, several other apparitions were observed: , , and ....
also 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 asteroid
Trojan (astronomy)
In astronomy, a Trojan is a minor planet or natural satellite that shares an orbit with a larger planet or moon, but does not collide with it because it orbits around one of the two Lagrangian points of stability , and , which lie approximately 60° ahead of and behind the larger body,...
s, 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
Geometric albedo
The geometric albedo of an astronomical body is the ratio of its actual brightness at zero phase angle to that of an idealized flat, fully reflecting, diffusively scattering disk with the same cross-section....
of 1.34. This very high albedo is the result of the sandblasting of particles from Saturn's E-ring
Rings of Saturn
The rings of Saturn are the most extensive planetary ring system of any planet in the Solar System. They consist of countless small particles, ranging in size from micrometres to metres, that form clumps that in turn orbit about Saturn...
, a faint ring composed of small, water-ice particles generated by Enceladus' south polar geysers.