Helene

Helene , in astronomy, one of the named moons, or natural satellites, of Saturn . Also known as Saturn XII (or S12), Helene is an irregularly shaped (nonspherical) body measuring about 22 mi (36 km) by 20 mi (32 km) by 18 mi (30 km); it orbits Saturn at a mean distance of 234,500 mi (377,400 km) and has an orbital period of 2.7369 earth days—the rotational period is unknown but is assumed to be the same as the orbital period. It was discovered by French astronomers P. Laques and J. Lecacheaux in 1980 during ground-based observations of Saturn. Another moon, Dione , is co-orbital with Helene; that is, Helene orbits Saturn at the same distance as Dione but precedes Dione by about 60°. Before the present name was adopted, the moon was referred to as "Dione-B" and "Electra."

Helene (Saturn XIII) One of the lesser satellites of Saturn, discovered in 1980 by Voyager 1, with a radius of 16 km; visual albedo 0.7.

Helene A satellite of Saturn, at a distance of 377 400 km; also known as Saturn XII. Helene's orbital period is 2.737 days. It shares the same orbit as the much larger satellite Dione, lying 60° ahead of it in the leading Lagrangian point. Helene is 36 × 32 × 30 km in size. It was discovered in 1980 from ground‐based observations.