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.

External link

• The American Association of Variable Star Observers
• WWW.SEMIREGULAR.COM WEB-service where variable star observers can manage and report their observations