Helene (moon)

Helene
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]
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 the Amazon 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".

Links

... | Telesto, Tethys, Calypso | Polydeuces, Dione, Helene | Rhea | ...

Saturn's natural satellites

Pan | Daphnis | Atlas | Prometheus | S/2004 S 6 | S/2004 S 4 | S/2004 S 3 | Pandora | Epimetheus and Janus | Mimas | Methone | Pallene | Enceladus | Telesto, Tethys, and Calypso | Polydeuces, Dione, and Helene | Rhea | Titan | Hyperion | Iapetus | Kiviuq | Ijiraq | Phoebe | Paaliaq | Skathi | Albiorix | S/2004 S 11 | Erriapo | Siarnaq | S/2004 S 13 | Tarvos | Mundilfari | 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/2004 S 16 | Ymir | S/2004 S 8

see also: Rings of Saturn | Cassini-Huygens | Themis

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