16 - White dwarf seismology: Influence of the constitutive physics on the period spectra

Summary

Abstract

We present the results of numerical experiments aimed at demonstrating how the g-mode period spectra of pulsating DA white dwarfs depend on the various components of the input physics. We take advantage of recent developments on many fronts of physics (equation of state, opacity, convection) to compare the theoretical pulsation periods of models with different pieces of the constitutive physics, but with otherwise fixed values of their stellar parameters. This exercise is necessary to assess the reliability of the pulsation analyses of white dwarfs which have started to come out.

Nous présentons les résultats de simulations numériques pour déterminer comment les périodes de pulsation (type g) des étoiles naines blanches DA dépendent des différentes composantes de la physique constitutive. A cet effet, nous avons utilisé des résultats récents au niveau de la physique de base (équation d'état, opacité, convection) pour comparer les périodes de pulsation de modèles stellaires ayant des paramètres fixes, mais qui différent au niveau de leur physique constitutive. Notre démarche est essentielle afin de pouvoir quantifier les premiers résultats d'analyses d'étoiles pulsantes qui commencent à être publiés.

Introduction

It is now well established that white dwarf stars become intrinsically variable during certain phases of their evolution. For the majority of them, the so-called DA white dwarfs (with atmospheres dominated by hydrogen), luminosity variations are observed when the stars have effective temperatures in the rather narrow interval 13,000 K ≳ T_eff ≳ 11,000 K (Wesemael et al. 1991).