An Etymological Dictionary of Astronomy and Astrophysics

A member of a large class of → pulsating stars of type A2-F6 with periods less than 1 day. They are similar to → Cepheids, except that their periods are much shorter and are less luminous. RR Lyrae stars belong to → Population II and are often found in → globular clusters (hence one of their older names cluster variables) or elsewhere in the → galactic halo. They are used as distance indicators (→ standard candle) out to more than 200 kpc.

See also: → Lyra; → star.