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Related papers: Accurate Diffusion Coefficients for Dense White Dw…

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Observations of galactic white dwarfs with Gaia have allowed for unprecedented modeling of white dwarf cooling, resolving core crystallization and sedimentary heating from neutron rich nuclei. These cooling sequences are sensitive to the…

Solar and Stellar Astrophysics · Physics 2021-07-07 M. E. Caplan , I. F. Freeman

Models of diffusion in white dwarfs universally rely on the coefficients calculated by Paquette et al. (1986). We present new calculations of diffusion coefficients based on an advanced microscopic theory of dense plasmas and a numerical…

Solar and Stellar Astrophysics · Physics 2014-10-29 D. Saumon , C. E. Starrett , J. Daligault

The diffusion of elements is a key process in understanding the unusual surface composition of white dwarfs stars and their spectral evolution. The diffusion coefficients of Paquette et al. (1986) have been widely used to model diffusion in…

Solar and Stellar Astrophysics · Physics 2020-06-17 R. A. Heinonen , D. Saumon , J. Daligault , C. E. Starrett , S. D. Baalrud , G. Fontaine

The diffusion coefficients of neutron rich nuclei in crystallizing white dwarf (WD) stars are essential microphysics input for modeling the evolution of the composition profile. Recently, molecular dynamics simulations have been used to…

Solar and Stellar Astrophysics · Physics 2023-04-17 Matthew E. Caplan

Translational diffusion coefficients are routinely estimated from molecular dynamics simulations. Linear fits to mean squared displacement (MSD) curves have become the de facto standard, from simple liquids to complex biomacromolecules.…

Computational Physics · Physics 2020-11-20 Jakob Tómas Bullerjahn , Sören von Bülow , Gerhard Hummer

Quantum corrections can be important for diffusion and the melting temperature of dense plasmas in compact astrophysical objects, particulary white dwarfs and neutron stars. Typically ions in these systems are modeled classically, but…

Solar and Stellar Astrophysics · Physics 2015-03-19 Justin Mason

Pulsating white dwarfs provide constraints to the evolution of progenitor stars. We revise He-burning stellar models, with particular attention to core convection and to its connection with the nuclear reactions powering energy generation…

Astrophysics · Physics 2009-11-07 Oscar Straniero , Inma Dominguez , Gianluca Imbriani , Luciano Piersanti

A practical correction formula relating the self-diffusion coefficient of dense liquids from molecular dynamics simulations with periodic boundary conditions to the self-diffusion coefficient in the thermodynamic limit is discussed. This…

Statistical Mechanics · Physics 2024-02-15 Sergey Khrapak

In this paper we revisit the issue of the propagation of warps in thin and viscous accretion discs. In this regime warps are know to propagate diffusively, with a diffusion coefficient approximately inversely proportional to the disc…

High Energy Astrophysical Phenomena · Physics 2015-05-18 G. Lodato , D. Price

Thermal-diffusional pulsation behaviors in planar as well as outwardly and inwardly propagating white dwarf carbon flames are systematically studied. In the 1D numerical simulation, the asymptotic degenerate equation of state and simplified…

High Energy Astrophysical Phenomena · Physics 2017-05-31 Guangzheng Xing , Yibo Zhao , Mikhail Modestov , Cheng Zhou , Yang Gao , Chung K. Law

We present a theoretical description of macroscopic diffusion caused by convective overshoot in pure-hydrogen DA white dwarfs using three-dimensional (3D), closed-bottom, radiation hydrodynamics CO$^5$BOLD simulations. We rely on a new grid…

Solar and Stellar Astrophysics · Physics 2019-07-10 Tim Cunningham , Pier-Emmanuel Tremblay , Bernd Freytag , Hans-Günther Ludwig , Detlev Koester

Self-diffusion coefficients, $D^*$, are routinely estimated from molecular dynamics simulations by fitting a linear model to the observed mean-squared displacements (MSDs) of mobile species. MSDs derived from simulation exhibit statistical…

Statistical Mechanics · Physics 2026-01-05 Andrew R. McCluskey , Samuel W. Coles , Benjamin J. Morgan

White dwarfs with metal-polluted atmospheres have been studied widely in the context of the accretion of rocky debris from evolved planetary systems. One open question is the geometry of accretion and how material arrives and mixes in the…

Diffusion in coulomb crystals can be important for the structure of neutron star crusts. We determine diffusion constants $D$ from molecular dynamics simulations. We find that $D$ for coulomb crystals with relatively soft-core $1/r$…

Solar and Stellar Astrophysics · Physics 2015-03-19 J. Hughto , A. S. Schneider , C. J. Horowitz , D. K. Berry

Reliable modeling of the atmospheres of cool white dwarfs is crucial for understanding the atmospheric evolution of these stars and for accurate white dwarfs cosmochronology. Over the last decade {\it ab initio} modeling entered many…

Solar and Stellar Astrophysics · Physics 2015-05-20 Piotr M. Kowalski

White Dwarf luminosities are powerful age indicators, whose calibration should be based on reliable models. We discuss the uncertainty of some chemical and physical parameters and their influence on the age estimated by means of white dwarf…

Astrophysics · Physics 2009-11-07 P. G. Prada Moroni , O. Straniero

Cooling ages of white dwarfs are routinely determined by mapping effective temperatures and masses to ages using evolutionary models. Typically, the reported uncertainties on cooling ages only consider the error propagation of the…

Solar and Stellar Astrophysics · Physics 2025-03-12 Praneet Pathak , Simon Blouin , Falk Herwig

An accurate assessment of white dwarf cooling times is paramount to place white dwarf cosmochronology of Galactic populations on more solid grounds. This issue is particularly relevant in view of the enhanced observational capabilities…

Solar and Stellar Astrophysics · Physics 2015-06-16 Maurizio Salaris , Leandro G. Althaus , Enrique García-Berro

We explore the effects of element diffusion due to gravitational settling and thermal and chemical diffusion on the pulsational properties of DA white dwarfs. To this end, we employ an updated evolutionary code coupled with a pulsational,…

Astrophysics · Physics 2009-11-07 A. H. Corsico , O. G. Benvenuto , L. G. Althaus , A. M. Serenelli

Understanding the transport behavior of quantum many-body systems constitutes an important physical endeavor, both experimentally and theoretically. While a reliable classification into normal and anomalous dynamics is known to be…

Statistical Mechanics · Physics 2025-06-11 Jiaozi Wang , Mats H. Lamann , Robin Steinigeweg , Jochen Gemmer
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