Helene (moon)

Pierre Laques, Jean Lecacheux

Helene ( Saturn XII ) is a small ( the siebzehntgrößte ) moon of the planet Saturn.

Discovery

Helene was discovered in the French Pyrenees on 1 March 1980 by the astronomers Pierre and Jean Laques Lecacheux at the observatory on the Pic du Midi. It was initially provisional designation S / 1980 S 6th 1988, they officially named after Helen, an Amazon from Greek mythology, who died in the fight with the hero Achilles.

Path data

Helene orbits Saturn at an average distance of 377,420 km in 65 hours and 41 minutes. The track has an eccentricity of 0.0071 and 0.21 ° inclined relative to the equatorial plane of the Saturn.

It is one of two small moons on the path of the large moon Dione. Helene runs Dione at an angular distance of 60 ° ahead in the leading Lagrange point L4. The following L5 Lagrange point of the moon Polydeuces Dione at an angular distance of 60 ° runs behind.

Before it received its official name, Helene was commonly referred to as " Dione B".

Structure and physical data

Helene is an irregularly shaped body with dimensions of 36 × 32 × 30 km. Their low density of 0.5 g/cm3 indicates that it is composed mainly of water ice and small amounts of silicate rock.

Helene rotates in 65 hours and 41 minutes around its own axis and thus has, as the Earth's moon, a tidal locking on. It has a light surface with an albedo of 0.6, i.e., 60 % of the incident solar light is reflected. From Earth, seen she is a very light faint object with an apparent magnitude of 18.4 m.

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