Toward High Precision Seismic Studies of White Dwarf Stars: Parametrization of the Core and Tests of Accuracy

TL;DR

This paper introduces a new parametrization method for modeling the chemical profile in white dwarf cores, enhancing the accuracy of seismic studies by using Akima splines and validating against evolutionary models.

Contribution

It presents a novel parametrization technique for white dwarf core chemistry using Akima splines, improving seismic modeling accuracy.

Findings

The new parametrization accurately reproduces full evolutionary models.

Tests demonstrate high precision in seismic modeling applications.

The method effectively captures complex chemical stratification.

Abstract

We present a prescription for parametrizing the chemical profile in the core of white dwarfs in the light of the recent discovery that pulsation modes may sometimes be deeply confined in some cool pulsating white dwarfs. Such modes may be used as unique probes of the complicated chemical stratification that results from several processes that occurred in previous evolutionary phases of intermediate-mass stars. This effort is part of our ongoing quest for more credible and realistic seismic models of white dwarfs using static, parametrized equilibrium structures. Inspired from successful techniques developed in design optimization fields (such as aerodynamics), we exploit Akima splines for the tracing of the chemical profile of oxygen (carbon) in the core of a white dwarf model. A series of tests are then presented to better seize the precision and significance of the results that can be obtained in an asteroseismological context. We also show that the new parametrization passes an essential basic test, as it successfully reproduces the chemical stratification of a full evolutionary model.