The pulsating low-mass He-core white dwarfs

TL;DR

This paper provides a detailed theoretical analysis of the seismic properties of low-mass helium-core white dwarfs, aiming to support the interpretation of their observed pulsations and advance asteroseismology.

Contribution

It offers the first comprehensive theoretical models of pulsating low-mass He-core white dwarfs to aid in understanding their observed variability.

Findings

Identification of key seismic signatures of low-mass He-core WDs

Prediction of pulsation modes consistent with observed variables

Framework for interpreting future asteroseismological data

Abstract

Recent years have witnessed the discovery of many low-mass ($\lesssim 0.45 M_{\odot}$) white dwarf (WD) stars --- expected to harbor He cores--- in the field of the Milky Way and in several galactic globular and open clusters. Recently, three pulsating objects of this kind have been discovered: SDSS J1840+6423, SDSS J1112+1117, and SDSS J1518+0658. Motivated by these very exciting findings, and in view of the valuable asteroseismological potential of these objects, we present here the main outcomes of a detailed theoretical study on the seismic properties of low-mass He-core WDs based on fully evolutionary models representative of these objects. This study is aimed to provide a theoretical basis from which to interpret present and future observations of variable low-mass WDs.