Helene (həlēnˈ, hĕlˈənə) [key], 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."

The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.

More on Helene from Fact Monster:

  • Mount Saint Helens - Dormant since 1857, Mount St. Helens erupted on May 18, 1980 in one of the largest volcanic explosions in North American history.
  • Helen Jacobs - Helen Jacobs Born: Aug. 6, 1908 Tennis 4-time winner of U.S. Championship (1932-35); Wimbledon ...
  • Helen Hayes - Hayes, Helen Hayes, Helen, 1900–1993, American actress, b. Washington, D.C., as Helen Hayes ...
  • Helen Hayes - Helen Hayes actress Born: 10/10/1900 Birthplace: Washington D.C. Academy and Tony Award winning ...
  • Helen - Helen Helen, in Greek mythology, the most beautiful of women; daughter of Leda and Zeus, and sister ...

See more Encyclopedia articles on: Astronomy: General

Play Hangman

Play Poptropica

Play Quizzes

Play Tic Tac Toe