variable star

noun

, Astronomy.

1. a star that varies markedly in brightness from time to time.

variable star

noun

1. 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

variable star

1. 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.

Word History and Origins

Origin of variable star¹

First recorded in 1780–90

Example Sentences

That meant that these variable stars, called Cepheids, could be used to estimate cosmic distances.

From Science News

The law of change in a variable star is represented to the eye by a curve in the following way.

From Project Gutenberg

Another variable star showing some unique features is Eta Aquil.

From Project Gutenberg

The most interesting variable star in the heavens is Algol (the demon), in the constellation Perseus.

From Project Gutenberg

For the other leading type of variable star, Algol, of which mention has already been made, is the best instance.

From Project Gutenberg

What does your wisdom make of that wandering and variable star behind those apple boughs?'

From Project Gutenberg