Helene (moon)
From Wikipedia, the free encyclopedia
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| Discovery | |
|---|---|
| Discovered by: | Laques and Lecacheux |
| Discovery date: | March 1, 1980 |
| Orbital characteristics | |
| Semi-major axis: | 377,396 km |
| Eccentricity: | 0.0022 |
| Orbital period: | 2.736915 d [1] |
| Inclination: | 0.199° (to Saturn's equator) |
| Satellite of: | Saturn |
| Physical characteristics | |
| Dimensions: | 36 × 32 × 30 km |
| Mean radius: | 16 km |
| Rotation period: | assumed synchronous |
| Axial tilt: | zero |
| Albedo: | 1.67 ± 0.20 (geometric)[1] |
Helene (hel'-e-nee, sometimes he-lee'-nee, /ˈhɛləni/, /həˈliːni/, 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.
It is co-orbital with Dione and located in its leading Lagrangian point (L4) and hence, before it received its permanent name it was usually referred to as Dione B.
[edit] References
- ^ A. Verbiscer et al. (2007). "Enceladus: Cosmic Graffiti Artist Caught in the Act". Science 315: 815.
[edit] External links
| Moons of Saturn | |
|---|---|
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Generally listed in increasing distance from Saturn
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| Ring shepherds | Pan · Daphnis · Atlas · Prometheus · S/2004 S 6 · S/2004 S 4 · S/2004 S 3 · Pandora |
| Co-orbitals | Epimetheus · Janus |
| Inner large and Trojan | Mimas · Methone · Pallene · Enceladus · Tethys (trojans Telesto, Calypso) · Dione (trojans Helene, Polydeuces) |
| Outer large | Rhea · Titan · Hyperion · Iapetus |
| Inuit group | Kiviuq · Ijiraq · Paaliaq · S/2004 S 11 · Siarnaq |
| Norse group | Phoebe · Skathi · S/2006 S 8 · S/2004 S 13 · S/2006 S 4 · S/2004 S 19 · Mundilfari · S/2006 S 6 · S/2006 S 1 · S/2004 S 17 · Narvi · S/2004 S 15 · S/2004 S 10 · Suttungr · S/2004 S 12 · S/2004 S 18 · S/2004 S 9 · S/2004 S 14 · S/2004 S 7 · Thrymr · S/2006 S 3 · S/2006 S 7 · S/2006 S 2 · S/2004 S 16 · Ymir · S/2006 S 5 · S/2004 S 8 |
| Gallic group | Albiorix · Erriapo · Tarvos |
