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Related papers: Diffusion coefficients in white dwarfs

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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

Diffusion coefficients are essential microphysics input for modeling white dwarf evolution, as they impact phase separation at crystallization and sedimentary heat sources. Present schemes for computing diffusion coefficients are accurate…

Solar and Stellar Astrophysics · Physics 2022-04-06 M. E. Caplan , E. B. Bauer , I. F. Freeman

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

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

We calculate interdiffusion coefficients in a two-component, weakly or strongly coupled ion plasma (gas or liquid, composed of two ion species immersed into a neutralizing electron background). We use an effective potential method proposed…

Solar and Stellar Astrophysics · Physics 2015-06-22 M. V. Beznogov , D. G. Yakovlev

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

We propose a joint experimental and theoretical approach to measure the self-diffusion in a laser-cooled trapped ion cloud where part of the ions are shelved in a long-lived dark state. The role of the self-diffusion coefficient in the…

We investigate the evolution of cooling helium atmosphere white dwarfs using a full evolutionary code, specifically developed for following the effects of element diffusion and gravitational settling on white dwarf cooling. The major…

Astrophysics · Physics 2016-08-16 James MacDonald , Margarita Hernanz , Jordi José

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

Collisional plasma shocks generated from supersonic flows are an important feature in many astrophysical and laboratory high-energy-density plasmas. Compared to single-ion-species plasma shocks, plasma shock fronts with multiple ion species…

Plasma Physics · Physics 2023-04-05 F. Chu , A. L. LaJoie , B. D. Keenan , L. Webster , S. J. Langendorf , M. A. Gilmore

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

Diffusion coefficients for crystallized Coulomb plasmas are essential microphysics input for modeling white dwarf cores and neutron star crusts but are poorly understood. In this work we present a model for diffusion in Coulomb crystals. We…

Plasma Physics · Physics 2024-09-13 M. E. Caplan , D. Yaacoub

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…

In this paper we study the diffusion approximation of a swarming model given by a system of interacting Langevin equations with nonlinear friction. The diffusion approximation requires the calculation of the drift and diffusion coefficients…

Numerical Analysis · Mathematics 2015-05-08 V. Bonnaillie-Noël , J. A. Carrillo , T. Goudon , G. A. Pavliotis

The diffusion coefficients of heavy quarks from the coherent color electromagnetic fields which are generated in the early stage of relativistic heavy-ion collisions are calculated at midrapidity, and compared with those obtained from…

Nuclear Theory · Physics 2015-12-18 Taesoo Song , Thomas Epelbaum

We calculate the momentum diffusion coefficient for heavy quarks in SU(3) gluon plasma at temperatures 1-2 times the deconfinement temperature. The momentum diffusion coefficient is extracted from a Monte Carlo calculation of the…

High Energy Physics - Lattice · Physics 2012-11-13 Debasish Banerjee , Saumen Datta , Rajiv V. Gavai , Pushan Majumdar

-We have performed a new efficient method to calculate numerically the transport coefficients at high temperature. The collision theory was treated to study singularities that occur when evaluating the collision cross section. The transport…

Plasma Physics · Physics 2015-01-30 Ali Mahfouf , Pascal André , Géraldine Faure

Recent studies of the atmospheres of carbon-rich (DQ) white dwarfs have demonstrated the existence of two different populations that are distinguished by the temperature range, but more importantly, by the extremely high masses of the…

Solar and Stellar Astrophysics · Physics 2020-03-25 D. Koester , S. O. Kepler , A. W. Irwin

Analysis of signal fluctuations of a locally fixed probe, caused by molecules diffusing under the probe, can be used to determine diffusion coefficients. Theoretical treatments so far have been limited to point-like particles or to…

Statistical Mechanics · Physics 2015-06-18 Susanne Hahne , Philipp Maass

We study diffusion coefficients of liquid domains by explicitly taking into account the two-layered structure called leaflets of the bilayer membrane. In general, the velocity fields associated with each leaflet are different and the layers…

Soft Condensed Matter · Physics 2015-06-18 Kazuhiko Seki , Saurabh Mogre , Shigeyuki Komura
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