New Conductive Opacities for White Dwarf Envelopes

Abstract

Thanks to their continuous cooling and relative simplicity, white dwarf stars are routinely used to measure the ages of stellar populations. The usefulness of white dwarfs as cosmochronometers depends on the availability of accurate cooling models. A key ingredient of those models are the conductive opacities, which largely govern the cooling rate. In this work, we present improved conductive opacities for the regime of moderate coupling and moderate degeneracy that characterizes an important portion of the envelopes of DA and DB white dwarfs. We find differences of up to a factor 3 between our calculations and the commonly used opacities of Cassisi et al. (2007), which we attribute to an improved account of electron-electron scattering. The cooling models are strongly affected by those changes in the conductive opacities: the age of a 4000 K white dwarf can be reduced by as much as 2 Gyr. We provide analytical fits to our new opacities to facilitate the implementation of this important effect in white dwarf evolution codes.

arXiv comment11 pages, 6 figures, 3 tables. Accepted for publication in The Astrophysical Journal

References in corpus (38)

• Gaia Data Release 2. Summary of the contents and survey properties
• The Gaia mission
• The Ages of Stars
• Updated Electron-Conduction Opacities: The Impact on Low-Mass Stellar Models
• A Comprehensive Spectroscopic Analysis of DB White Dwarfs
• Neutron stars - cooling and transport
• New cooling sequences for old white dwarfs
• A white dwarf cooling age of 8 Gyr for NGC 6791 from physical separation processes
• Spectroscopic analysis of DA white dwarfs with 3D model atmospheres
• Cooling Models for Old White Dwarfs
• Rare White dwarf stars with carbon atmospheres
• Core crystallization and pile-up in the cooling sequence of evolving white dwarfs
• The Ages of the Thin Disk, Thick Disk, and the Halo from Nearby White Dwarfs
• The 100 pc White Dwarf Sample in the SDSS Footprint
• Detailed Spectroscopic and Photometric Analysis of DQ White Dwarfs
• A large stellar evolution database for population synthesis studies: VI. White dwarf cooling sequences
• A cooling anomaly of high-mass white dwarfs
• Analysis of Helium-Rich White Dwarfs Polluted by Heavy Elements in the Gaia Era
• An Age Difference of 2 Gyr between a Metal-Rich and a Metal-Poor Globular Cluster
• Hot DQ White Dwarfs: Something Different
• Comparison of theoretical white dwarf cooling timescales
• Gravitational Settling of 22Ne in Liquid White Dwarf Interiors
• DB white dwarfs in the Sloan Digital Sky Survey Data Release 10 and 12
• A New Generation of Cool White Dwarf Atmosphere Models. I. Theoretical Framework and Applications to DZ Stars
• Crystallization of Carbon Oxygen Mixtures in White Dwarf Stars
• The Age of the Milky Way Inner Halo
• White Dwarf Cosmochronology in the Solar Neighborhood
• On the Spectral Evolution of Helium-Atmosphere White Dwarfs Showing Traces of Hydrogen
• Density-functional calculations of transport properties in the non-degenerate limit and the role of electron-electron scattering
• The Canada-France Imaging Survey: Reconstructing the Milky Way Star Formation History from its White Dwarf Population
• The effect of ${}^{22}$Ne diffusion in the evolution and pulsational properties of white dwarfs with solar metallicity progenitors
• Evolution of white dwarf stars with high-metallicity progenitors: the role of 22Ne diffusion
• Gravitational settling of 22Ne and white dwarf evolution
• The Age of the Galactic Stellar Halo from Gaia White Dwarfs
• The White Dwarf Age of NGC 2477
• A Model of Electron Transport in Dense Plasmas Spanning Temperature Regimes
• Potential of mean force for electrical conductivity of dense plasmas
• Correlations Between Conduction Electrons in Dense Plasmas

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