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Title: Mixing and overshooting in surface convection zones of DA white dwarfs: first results from antares

Abstract

In this work, we present results of a large, high-resolution 3D hydrodynamical simulation of the surface layers of a DA white dwarf (WD) with T eff = 11 800 K and log (g) = 8 using the ANTARES code, the widest and deepest such simulation to date. Our simulations are in good agreement with previous calculations in the Schwarzschild-unstable region and in the overshooting region immediately beneath it. Farther below, in the wave-dominated region, we find that the rms horizontal velocities decay with depth more rapidly than the vertical ones. Since mixing requires both vertical and horizontal displacements, this could have consequences for the size of the region that is well mixed by convection, if this trend is found to hold for deeper layers. Lastly, we discuss how the size of the mixed region affects the calculated settling times and inferred steady-state accretion rates for WDs with metals observed in their atmospheres.

Authors:
 [1];  [2];  [3]
  1. Univ. of Vienna, Wien (Austria); Univ. Göttingen (Germany)
  2. Brandenburg University of Technology Cottbus-Senftenberg (Germany)
  3. Univ. of Texas, Austin, TX (United States)
Publication Date:
Research Org.:
Univ. of Texas, Austin, TX (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1512961
Grant/Contract Number:  
SC0010623
Resource Type:
Accepted Manuscript
Journal Name:
Monthly Notices of the Royal Astronomical Society
Additional Journal Information:
Journal Volume: 474; Journal Issue: 4; Journal ID: ISSN 0035-8711
Publisher:
Royal Astronomical Society
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; convection; stars: atmospheres; stars: interiors; white dwarfs

Citation Formats

Kupka, F., Zaussinger, F., and Montgomery, M. H. Mixing and overshooting in surface convection zones of DA white dwarfs: first results from antares. United States: N. p., 2017. Web. doi:10.1093/mnras/stx3119.
Kupka, F., Zaussinger, F., & Montgomery, M. H. Mixing and overshooting in surface convection zones of DA white dwarfs: first results from antares. United States. doi:10.1093/mnras/stx3119.
Kupka, F., Zaussinger, F., and Montgomery, M. H. Tue . "Mixing and overshooting in surface convection zones of DA white dwarfs: first results from antares". United States. doi:10.1093/mnras/stx3119. https://www.osti.gov/servlets/purl/1512961.
@article{osti_1512961,
title = {Mixing and overshooting in surface convection zones of DA white dwarfs: first results from antares},
author = {Kupka, F. and Zaussinger, F. and Montgomery, M. H.},
abstractNote = {In this work, we present results of a large, high-resolution 3D hydrodynamical simulation of the surface layers of a DA white dwarf (WD) with Teff = 11 800 K and log (g) = 8 using the ANTARES code, the widest and deepest such simulation to date. Our simulations are in good agreement with previous calculations in the Schwarzschild-unstable region and in the overshooting region immediately beneath it. Farther below, in the wave-dominated region, we find that the rms horizontal velocities decay with depth more rapidly than the vertical ones. Since mixing requires both vertical and horizontal displacements, this could have consequences for the size of the region that is well mixed by convection, if this trend is found to hold for deeper layers. Lastly, we discuss how the size of the mixed region affects the calculated settling times and inferred steady-state accretion rates for WDs with metals observed in their atmospheres.},
doi = {10.1093/mnras/stx3119},
journal = {Monthly Notices of the Royal Astronomical Society},
number = 4,
volume = 474,
place = {United States},
year = {2017},
month = {12}
}

Journal Article:
Free Publicly Available Full Text
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Cited by: 4 works
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