A deeper understanding of white dwarf interiors

Abstract

A detailed record of the physical processes that operate during post-main-sequence evolution is contained in the internal chemical structure of white dwarfs. Global pulsations allow us to probe the stellar interior through asteroseismology, revealing the signatures of prior nuclear burning, mixing, and diffusion in these stars. I review the rapid evolution of structural models for helium-atmosphere variable (DBV) white dwarfs over the past five years, and I present a new series of model-fits using recent observations to illustrate the relative importance of various interior structures. By incorporating physically motivated C/O profiles into double-layered envelope models for the first time, I finally identify an optimal asteroseismic model that agrees with both diffusion theory and the expected nuclear burning history of the progenitor. I discuss the implications of this fundamental result, and I evaluate the prospects for continued progress in the future.

5 pages, 2 figures, 1 table, Accepted for MNRAS Letters

References in corpus (17)

• The cooling of CO white dwarfs: influence of the internal chemical distribution
• The chemical composition of White Dwarfs as a test of convective efficiency during core He-burning
• A Strong Test of Electro-Weak Theory using Pulsating DB White Dwarf Stars as Plasmon Neutrino Detectors
• Stellar Structure Modeling using a Parallel Genetic Algorithm for Objective Global Optimization
• Measuring ^{12}C(&alpha,&gamma)^{16}O from White Dwarf Asteroseismology
• Thick to Thin: The Evolutionary Connection Between PG 1159 Stars and the Thin Helium-Enveloped Pulsating White Dwarf GD 358
• The core/envelope symmetry in pulsating stars
• A CCD Time-Series Photometer
• White Dwarf Asteroseismology and the ^12C(alpha,gamma)^16O Rate
• The Everchanging Pulsating White Dwarf GD358
• Preliminary Constraints on 12C(alpha,gamma)16O from White Dwarf Seismology
• Genetic-Algorithm-based Asteroseismological Analysis of the DBV White Dwarf GD 358
• Probing the core and envelope structure of DBV white dwarfs
• The asteroseismological potential of the pulsating DB white dwarf stars CBS 114 and PG 1456+103
• The double-layered chemical structure in DB white dwarfs
• A new look at the pulsating DB white dwarf GD 358:Line-of-sight velocity measurements and constraints on model atmospheres
• An asteroseismic test of diffusion theory in white dwarfs

Cited by in corpus (17)

• White Dwarf Mass Distribution in the SDSS
• Carbon Deficiency in Externally-Polluted White Dwarfs: Evidence for Accretion of Asteroids
• A Stellar Model-fitting Pipeline for Asteroseismic Data from the Kepler Mission
• Astromaterial Science and Nuclear Pasta
• Seismological studies of ZZ Ceti stars. I. The model grid and the application to individual stars
• Diffusion of Neon in White Dwarf Stars
• The potential of asteroseismology for probing the core chemical stratification in white dwarf stars
• Asteroseismology
• Analysis of IUE spectra of helium-rich white dwarf stars
• Asteroseismology of the Kepler field DBV White Dwarf - It's a hot one!
• Asteroseismic constraints on diffusion in WD envelopes
• The Impact of White Dwarf Luminosity Profiles on Oscillation Frequencies
• Toward High Precision Seismic Studies of White Dwarf Stars: Parametrization of the Core and Tests of Accuracy
• The Large Array Survey Telescope -- Science Goals
• Direct MD simulation of liquid-solid phase equilibria for two-component plasmas
• An observer's view on the future of asteroseismology
• Neutron rich matter, neutron stars, and their crusts