There are many types of variable stars, and their pulsations can be caused by various factors like:

* Cepheid variables: These stars pulsate in a regular, predictable way, with a period directly related to their luminosity. They are important tools for measuring distances in the universe.

* RR Lyrae variables: These stars are also pulsating and are often found in globular clusters. They are less luminous than Cepheid variables.

* Mira variables: These stars undergo very large changes in brightness over long periods.

* Eruptive variables: These stars are experiencing outbursts or explosions on their surface, causing changes in their brightness.

The term "pulsating star" is a more general term that can be used for any star that exhibits pulsations, regardless of the specific type.