Variable Stars

Variable Stars

Variable stars vary in the intensity of the light they emit. Changes in brightness can result from changes in size, mass, colour and/or temperature. Variable stars are grouped into three categories:

Pulsating expanding and contracting, causing them to change their brightness and size
Eclipsing partially blocks the light of another star as it passes in front of it
Eruptive sudden outbursts of radiant energy, which causes rapid brightening

Pulsating and Eruptive are both intrinsic variables because the stars change physically. Eclipsing variables are extrinsic because the change is caused by two stars, neither physically changing. [VH] {EP} {EB}