How do variable stars pulsate?
1 Answer
The "pulsations" are various forms of energy output variations. They are caused by variations in the size of the star.
Explanation:
Pulsating variable stars are intrinsic variables as their variation in brightness is due to a physical change within the star. In the case of pulsating variables this is due to the periodic expansion and contraction of the surface layers of the stars.
This means the star actually increases and decreases in size periodically. The different types of pulsating variable are distinguished by their periods of pulsation and the shapes of their light curves. These in turn are a function of the mass and evolutionary stage of a given star.
More details:
http://www.atnf.csiro.au/outreach/education/senior/astrophysics/variable_pulsating.html
Easy-to-understand discussion:
https://www.space.com/15396-variable-stars.html
