Seismic test of the mass-radius relationship of hydrogen-atmospheric white dwarf stars

TL;DR

This study analyzes the pulsation properties of ZZ Ceti white dwarf stars to test the empirical and seismic mass-radius relationships, revealing discrepancies up to 15% for massive stars and confirming the linear temperature-period relation.

Contribution

It provides a comprehensive statistical analysis of ZZ Ceti stars, testing the mass-radius relationship with Gaia data and pulsation analysis, highlighting systematic differences from theoretical models.

Findings

WMP distribution shows two main groups at ~254s and ~719s

Confirmed linear relationship between temperature and pulsation period

White dwarfs are larger than theoretical predictions by up to 15% for massive stars

Abstract

The pulsation of white dwarfs provides crucial information on stellar parameters for understanding the atmosphere and interior structure of these stars. In this study, we present a comprehensive statistical analysis of known ZZ Ceti stars from historical literature. Our dataset includes stellar parameters and oscillation properties from 339 samples, with 194 of them having undergone asteroseismological analysis. We investigated the empirical instability strip of ZZ Ceti stars and confirmed the linear relationship between temperature and weighted mean pulsation periods (WMP). We found that the WMP distribution is well-described with two groups of stars with peak values at $\sim254$ s and $\sim719$ s. Using seismic mass and trigonometrical radii derived from GAIA DR3 parallaxes, we tested the mass-radius relationship of white dwarfs through observational and seismic analysis of ZZ Cetis. They are generally larger than the theoretical values, with the discrepancy reaching up to $\sim15\%$ for massive stars with a mass estimated by seismology.