The Halo White Dwarf WD 0346+246 Revisited

Abstract

The extreme helium-rich atmospheric composition determined for the halo white dwarf WD 0346+246 is reexamined. This solution is shown to be improbable from an astrophysical point of view when accretion of hydrogen and metals from the interstellar medium is taken into account. An alternate solution is proposed where hydrogen and helium are present in the atmospheric regions in equal amounts. The best fit at Teff=3780 K, log g=8.34, and N(He)/N(H)=1.3 is achieved by including in the model calculations a bound-free opacity from the Lyman edge associated with the so-called dissolved atomic levels of the hydrogen atom, or pseudo-continuum opacity.

Accepted for publication in the Astrophysical Journal (Sept. 10, 2001 issue); 22 pages including 6 figures

References in corpus (4)

• Direct Detection of Galactic Halo Dark Matter
• High-velocity white dwarfs: thick disk, not dark matter
• A New Very Cool White Dwarf Discovered by the Sloan Digital Sky Survey
• Observations of Ultracool White Dwarfs

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