Toward ensemble asteroseismology of ZZ Ceti stars with fully evolutionary models

TL;DR

This study conducts an asteroseismological analysis of 44 ZZ Ceti stars using new evolutionary models, revealing diverse hydrogen layer thicknesses and precise stellar parameters, enhancing understanding of white dwarf properties.

Contribution

Introduces a new set of fully evolutionary models for ZZ Ceti stars and applies them to analyze 44 stars, improving characterization of their internal structures.

Findings

Diverse hydrogen-layer thicknesses in local white dwarfs.

Accurate modeling of G117-B15A's temperature and gravity.

Potential to determine global properties of ZZ Ceti stars.

Abstract

ZZ Ceti stars form the most numerous group of degenerate variable stars. They are otherwise normal DA (H-rich atmospheres) white dwarfs that exhibit pulsations. Here, we present an asteroseismological analysis for 44 bright ZZ Ceti stars based on a new set of fully evolutionary DA white dwarf models characterized by detailed chemical profiles from the centre to the surface. One of our targets is the archetypal ZZ Ceti star G117$-$B15A, for which we obtain an asteroseismological model with an effective temperature and a surface gravity in excellent agreement with the spectroscopy. The asteroseismological analysis of a set of 44 ZZ Ceti stars has the potential to characterize the global properties of the class, in particular the thicknesses of the hydrogen envelope and the stellar masses. Our results support the belief that white dwarfs in the solar neighbourhood harbor a broad range of hydrogen-layer thickness.