Astron. Astrophys. 343, L91-L93 (1999)

Letter to the Editor

Indication of singly ionized helium in the white dwarf GD 229

Matthew D. Jones ¹, Gerardo Ortiz ¹ and David. M. Ceperley <sup>2

1</sup> Theoretical Division, Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87545, USA
² Department of Physics and National Center for Supercomputing Applications, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, IL 61801, USA

Received 1 December 1998 / Accepted 25 January 1999

Abstract

We comment on the applicability of the stationary line argument recently used by Jordan et al. (1998) to account for the unusual absorption features in the observed optical spectra of GD 229. Moreover, we provide an alternative explanation based upon the existence of neutral and singly ionized atomic helium atoms as the main elements comprising the atmosphere of this magnetized white dwarf star.

Key words: stars: white dwarfs stars: magnetic fields stars: individual: GD 229 stars: individual: LB 11146B

Send offprint requests to: Matthew D. Jones

Correspondence to: mdj@lanl.gov

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Contents

• 1. Introduction
• 2. Background
• 3. Contributions from He⁺
• 4. Conclusions
• Acknowledgements
• References

© European Southern Observatory (ESO) 1999

Online publication: March 1, 1999
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