Starlight

Eclipsing Binary Star Light Curve

13.14 - Understand the light curves of the following variable stars:
b) eclipsing binary

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13.15 - Understand the causes of variability in the light curve of eclipsing binary stars

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13.18 - Understand how the period of an eclipsing binary star can be deduced from its light curve

Eclipsing binaries are a pair of stars that orbit each other. One will move in front and behind the other as seen from Earth.

Frequently one star is brighter than another and we can see the stars wink and dip as the darker star moves in front and behind it.

By charting the brightness of a binary star you can find its period. In the chart on the right the period would be from the 'dips' at 24 and 64 leading to a period of 30 hours.