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Helene (moon)
Encyclopedia
Helene is a moon
of Saturn
. It was discovered by Pierre Laques and Jean Lecacheux in 1980 from ground-based observations at Pic du Midi Observatory, and was designated . In 1988 it was officially named after Helen of Troy, who was the granddaughter of Cronus
(Saturn) in Greek mythology
. The moon is also designated (12), a number which it received in 1982, under the designation Dione B, because it is co-orbital with Dione
and located in its leading Lagrangian point
. It is one of four known trojan moons.
flybys of Saturn in the early 1980s allowed much closer views. The Cassini–Huygens mission, which went into orbit around Saturn in 2004, provided still better views, and allowed more in-depth analysis of the moon, including views of the surface under different lighting conditions. Some of the closest images of Helene to date are from the Cassini spacecraft's 1800 km flyby on March 3, 2010, and another very successful imaging sequence occurred in June 2011. There have been many other approaches over the course of the C-H mission, and future flybys may yield even more data.
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 by Pierre Laques and Jean Lecacheux in 1980 from ground-based observations at Pic du Midi Observatory, and was designated . In 1988 it was officially named after Helen of Troy, who was the granddaughter of Cronus
Cronus
In Greek mythology, Cronus or Kronos was the leader and the youngest of the first generation of Titans, divine descendants of Gaia, the earth, and Uranus, the sky...
(Saturn) in 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...
. The moon is also designated (12), a number which it received in 1982, under the designation Dione B, because it is co-orbital with Dione
Dione (moon)
Dione is a moon of Saturn discovered by Cassini in 1684. It is named after the titan Dione of Greek mythology. It is also designated Saturn IV.- Name :...
and located in its leading 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...
. It is one of four known trojan moons.
Exploration
Helene was initially observed from Earth in 1980, and VoyagerVoyager program
The Voyager program is a U.S program that launched two unmanned space missions, scientific probes Voyager 1 and Voyager 2. They were launched in 1977 to take advantage of a favorable planetary alignment of the late 1970s...
flybys of Saturn in the early 1980s allowed much closer views. The Cassini–Huygens mission, which went into orbit around Saturn in 2004, provided still better views, and allowed more in-depth analysis of the moon, including views of the surface under different lighting conditions. Some of the closest images of Helene to date are from the Cassini spacecraft's 1800 km flyby on March 3, 2010, and another very successful imaging sequence occurred in June 2011. There have been many other approaches over the course of the C-H mission, and future flybys may yield even more data.
Selected observations
Mostly raw greyscale images with near infrared or ultraviolet channels.  |
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External links
- Helene Profile by NASA's Solar System Exploration
- The Planetary Society: Helene
- Helene has two faces - The Planetary Society : Helene Mini Atlas - Mar. 11, 2010
- Cassini catches Helene - The Planetary Society : Video & Views - Jun. 20, 2011