The Onset of Chaos in Pulsating Variable Stars

TL;DR

This paper investigates the onset of chaos in pulsating variable stars, analyzing how stochastic fluctuations in their pulsation periods relate to stellar properties and recent detection methods.

Contribution

It provides new insights into the physical processes causing pulsation fluctuations and demonstrates recent advancements in detecting chaos in these stars.

Findings

Stochastic fluctuations are linked to star size and vary among star types.

Chaos detection in pulsating stars has become feasible with recent methods.

Fluctuations are random over short cycles but regular over long periods.

Abstract

Random changes in pulsation period occur in cool pulsating Mira variables, Type A, B, and C semiregular variables, RV Tauri variables, and in most classical Cepheids. The physical processes responsible for such fluctuations are uncertain, but presumably originate in temporal modifications of the envelope convection in such stars. Such fluctuations are seemingly random over a few pulsation cycles of the stars, but are dominated by the regularity of the primary pulsation over the long term. The magnitude of stochasticity in pulsating stars appears to be linked directly to their dimensions, although not in simple fashion. It is relatively larger in M supergiants, for example, than in short-period Cepheids, but is common enough that it can be detected in visual observations for many types of pulsating stars. Although chaos was discovered in such stars 80 years ago, detection of its general presence in the group has only been possible in recent studies.