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A photospheric metal line profile analysis of hot DA white dwarfs with circumstellar material

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journal contribution
posted on 24.04.2014, 10:27 by Nathan J. Dickinson, Martin A. Barstow, B. Y. Welsh
Some hot DA white dwarfs have circumstellar high ion absorption features in their spectra, in addition to those originating in the photosphere. In many cases, the line profiles of these absorbing components are unresolved. Given the importance of the atmospheric composition of white dwarfs to studies of stellar evolution, extra-solar planetary systems and the interstellar medium, we examine the effect of including circumstellar line profiles in the abundance estimates of photospheric metals in six DA stars. The photospheric C and Si abundances are reduced in five cases where the circumstellar contamination is strong, though the relative weakness of the circumstellar Si IV absorption introduces minimal contamination, resulting in a small change in abundance. The inability of previous, approximate models to reproduce the photospheric line profiles here demonstrates the need for a technique that accounts for the physical line profiles of both the circumstellar and photospheric lines when modelling these blended absorption features.

Funding

STFC

History

Citation

Monthly Notices of the Royal Astronomical Society, 2013, 428 (3), pp. 1873-1879

Author affiliation

/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and Astronomy

Version

VoR (Version of Record)

Published in

Monthly Notices of the Royal Astronomical Society

Publisher

Oxford University Press

issn

0035-8711

eissn

1365-2966

Copyright date

2012

Available date

24/04/2014

Publisher version

http://mnras.oxfordjournals.org/content/428/3/1873

Language

en