variable star

noun

Astronomy.

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

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

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.

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Word History and Origins

Origin of variable star¹

First recorded in 1780–90

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Example Sentences

Examples have not been reviewed.

HP Tau is known as a T Tauri star, a type of young variable star that hasn't begun nuclear fusion yet but is beginning to evolve into a hydrogen-fueled star similar to our Sun.

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A key rung relies on observations of variable stars called Cepheids.

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The approaches include looking at supernovae and variable stars in distant galaxies and measuring how fast they’re receding, as well as how far away they are.

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Much of their work was on variable stars.

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“Betelgeuse is a variable star. It changes with time..., and Antares is variable as well, but we don’t know the cycles as well,” Kafka says.

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variable resistor varia lectio

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