Helene (moon)
|
|
| |
| Discovery | |
|---|---|
| Discovered by | Laques and Lecacheux |
| Discovered in | March 1, 1980 |
| Orbital characteristics | |
| Semimajor axis | 377,396 km |
| Eccentricity | 0.0022 |
| Orbital period | 2.736915 d [1] (http://exp.arc.nasa.gov/downloads/celestia/data/solarsys.ssc) |
| Inclination | 0.199° (to Saturn's equator) |
| Satellite of | Saturn |
| Physical characteristics | |
| Mean diameter | 32 km (36 × 32 × 30) |
| Mass | ?kg |
| Mean density | ? g/cm3 |
| Surface gravity | ?m/s2 |
| Escape velocity | ?km/s |
| Rotation period | assumed synchronous |
| Axial tilt | zero |
| Albedo | ? |
| Surface temperature | ? K |
| Atmosphere | none |
Helene (hel'-e-nee, Greek ‘Ελένη) 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 Helene of Greek mythology. It is also designated as Saturn XII.
It is co-orbital with Dione and located in its leading Lagrangian point (L4) and hence, before it received its permanent name of "Helene" it was usually referred to as "Dione B".
External links
- The Planetary Society: Helene (http://www.planetary.org/saturn/helene.html)
| Saturn's natural satellites |
|---|
| Janus' group | Mimas | Enceladus | Tethys | Dione | Rhea | Titan | Hyperion | Iapetus | Inuit group | Gallic group | Norse group |
fr:Hélène (lune) nl:Helene (maan) nn:Saturnmånen Helene zh:土卫十二