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Variable stars are stars that change brightness. The change can vary from thousands of a magnitude to as much as twenty magnitudes over periods of a fraction of a second to years. So far, almost 150,000 variable stars are known and documented, and as many as thousands more are speculated to be variable. They change brightness due to several reasons. For example, pulsating variables shrink and swell due to internal forces. Similarly, an eclipsing binary will dim when obscured by a faint partner and then brightens when the occulting partner moves away. The different causes for light variation in variable star render stimulus for classifying stars into different categories. |
The Gamma Cassiopeiae, a eruptive variable star in Cassiopeia. |
Erasmus +
Eruptive variable star
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