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Astro*Dictionary by Michael Erlewine





1 article for "Cepheid Variable"

Cepheid Variable [Astro*Index]

Named after the star delta Cephei, a typical example and the first of this type discovered, another example being Polaris or alpha Ursae Minoris, the pole star; all are giant or supergiant yellow stars. The Cepheids are pulsating stars with periods ranging from a few days to several months and spectral types of F or G (at maximum light). All are reddest at minimum light but never have spectrum later than K. They are important because they are bright enough to be observed in other galaxies besides our own, such as Andromeda. The longer the period of a Cepheid, the more luminous it is; thus these stars have served as "candles" for exploring external galaxies such as the Magellanic Clouds. Over 600 Cepheids have been discovered in the Milky Way and other galaxies. This group of pulsating stars are often called classical Cepheids.

See also:
♦ Andromeda Galaxy ♦ Period-luminosity Relation ♦ Spectral Class ♦ Magellanic Clouds


Astro*Index Copyright © 1997 Michael Erlewine