Variable star

Most stars are of nearly constant luminosity. Our own Sun is a good example of one which goes through relatively little variation in brightness (usually about 0.1% over an 11 year solar cycle). Many stars, however, undergo significant variations in luminosity, and these are known as variable stars. Variable stars may be either intrinsic or extrinsic.

Variable star observations

Variable stars are generally analysed using photometry and photospectrometry. Observations of their brightness compared to non-variable stars of known magnitude can be used to establish a light curve. For regular variables, the period of variation and its amplitude can be very well established; for many variable stars, though, these quantities may vary slowly over time, or even from one period to the next. Peak brightnesses in the light curve are known as maxima, while troughs are known as minima.

Related Topics:
Photometry - Photospectrometry - Light curve - Period - Amplitude

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