variable star

noun Astronomy.

a star that varies markedly in brightness from time to time.
Also called variable.

Origin of variable star

First recorded in 1780–90

Words nearby variable star

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British Dictionary definitions for variable star

variable star

noun

any star that varies considerably in brightness, either irregularly or in regular periods. Intrinsic variables, in which the variation is a result of internal changes, include novae, supernovae, and pulsating stars See also eclipsing binary

Scientific definitions for variable star

variable star

A star whose actual or observed brightness varies periodically. These changes can occur with varying degrees of regularity and intensity, over times ranging from a fraction of a second to many years. Intrinsic variation occurs because of changes of the star itself, often due to internal vibration or eruptions, or to influx of nearby material. Cepheids and novae are examples of intrinsically variable stars. Extrinsic variation in a star's observed brightness that does not reflect physical changes in the star also occur, as when a darker star periodically eclipses a brighter star in an eclipsing binary system, or with the rotation of a star.