Variable Star
A variable star is a star whose brightess as seen from Earth (its apparent magnitude) fluctuates.
This variation may be caused by a change in emitted light or by something partly blocking the light, so variable stars are classified as either:
- Intrinsic variables, whose luminosity actually changes; for example, because the star periodically swells and shrinks.
- Extrinsic variables, whose apparent changes in brightness are due to changes in the amount of their light that can reach Earth; for example, because the star has an orbiting companion that sometimes eclipses it.
Many, possibly most, stars have at least some variation in luminosity: the energy output of our Sun, for example, varies by about 0.1% over an 11 year solar cycle.
Read more about Variable Star: Discovery, Detecting Variability, Variable Star Nomenclature, Classification
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... Stars with planets may also show brightness variations if their planets pass between the earth and the star ...
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... Peltier Award in 1981 for his variable star and lunar occultation observations and contributions to artificial satellite programs ... The American Association of Variable Star Observers honoured him with the Merit Award in 1988, for his record of more than 50,000 observations in the AAVSO International Database and for 54-year ... He also won the Amateur Achievement Award of the Astronomical Society of the Pacific for his variable star and occultation observations in 1997 ...
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