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Cassini image of Helene against the backdrop of Saturn's clouds (March 3, 2010)
|Discovered by||Laques and
|Discovery site||Pic du Midi Observatory|
|Discovery date||March 1, 1980|
|Semi-major axis||377,396 km|
|Orbital period||2.736915 d |
|Inclination||0.199° (to Saturn's equator)|
|Dimensions||43.4×38.2×26 km |
|Mean radius||17.6 ± 0.4 km |
|Albedo||1.67 ± 0.20 (geometric) |
Helene ( // HEL-ə-nee;[a] Greek: Ἑλένη) 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 S/1980 S 6. 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 Saturn XII (12), a number which it received in 1982, under the designation Dione B,[b] because it is co-orbital with Dione and located in its leading Lagrangian point (L4). It is one of four known trojan moons.
Helene was initially observed from Earth in 1980, and Voyager 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 Cassini mission, and future flybys may yield additional data.
Mostly raw greyscale images with near infrared or ultraviolet channels.
|Wikimedia Commons has media related to: Helene|
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