Structure and evolution of pulsating hot subdwarfs

TL;DR

This paper reviews the structure and evolution of pulsating hot subdwarfs, highlighting how their seismic properties inform us about their internal structure and evolutionary history, with some unexpected findings.

Contribution

It provides a comprehensive overview of the seismic analysis of hot subdwarfs, emphasizing new insights into their internal structure and evolution.

Findings

Seismic fits confirm many evolutionary predictions.

Pulsations reveal detailed internal structure.

Some surprises challenge existing models.

Abstract

Hot subdwarfs are evolved low--mass stars that have survived core helium ignition and are now in (or recently finished with) the core helium burning stage. At the hot end of the Horizontal Branch (HB), many of these stars are multiperiodic pulsators. These pulsations have revealed details of their global and internal structure, and provide important constraints on the origin of hot HB stars. While many features of their structure deduced from seismic fits have confirmed what we expected from evolutionary considerations, there have been some surprises as well.