Stars That Breathe

Stars which show a variation in their brightness are called variable stars. Pulsating variables are intrinsic variable stars whose brightness changes with a reasonably fixed period. The pulsation can be radial or non-radialPulsationradialPulsationnon-radial. Radial pulsation is caused by the \(\kappa \) -mechanism, which operates in classical Cepheid variablesCepheid variable. The restoring force in non-radial pulsations can be either pressure of buoyancy. Main sequenceMain sequence stars like the Sun display p-mode pulsationPulsationp-mode, which are acoustic waves confined in concentric shells while g-mode oscillations are confined to stellar interior. In contrast, white dwarf stars show g-mode pulsationPulsationg-mode of the surface. Many of the pulsating classes fall on the instability stripInstability strip of the Hertzsprung-Russell diagramHertzsprung-Russell diagram. Pulsations in stars carry information about their interior structures. We review briefly few classes of stars and point out the importance of studying stellar pulsations.