Astron. Astrophys. 337, L13-L16 (1998)

Letter to the Editor

Four magnetic DB white dwarfs discovered by the Hamburg/ESO survey ^*

D. Reimers ¹, S. Jordan ², V. Beckmann ¹, N. Christlieb ¹ and L. Wisotzki <sup>1

1</sup> Hamburger Sternwarte, Universität Hamburg, Gojenbergsweg 112, D-21029 Hamburg, Germany
² Institut für Theoretische Physik und Astrophysik der Universität Kiel, D-24098 Kiel, Germany

Received 1 July 1998 / Accepted 15 July 1998

Abstract

We report on seven peculiar faint blue stars found in the course of the Hamburg/ESO survey (HES) which appear to be magnetic white dwarfs (WDs) with non-hydrogen spectra. We show in particular that four of them (HE 0338-3853, HE 0107-0158, HE 0026-2150, and HE 0003-5701) have He I lines split by magnetic fields of roughly 20 MG, since the components of He I 5876 Å and He I 4929 Å can be identified unambiguously in their spectra, and the , components can be identified in the spectra of two of these stars (HE 0338-3853 and HE 0003-5701). Besides GD 229, these are the first magnetic DB white dwarfs discovered so far.

In addition, three further WDs with broad, unidentifiable features have been found: HE 1043-0502, HE 0236-2656, and HE 0330-0002. We argue that in all three of these stars H I can not be responsible for the broad features, and He I most probably not for the features in HE 0236-2656 and HE 0330-0002, while it still remains possible that the broad features of HE 1043-0502 are due to He I.

Key words: stars: white dwarfs stars: magnetic fields

* Based on observations at the European Southern Observatory, La Silla, Chile

Send offprint requests to: D. Reimers (e-mail: dreimers@hs.uni-hamburg.de)

SIMBAD Objects

Contents

• 1. Introduction
• 2. Observations
• 3. Interpretation
  • 3.1. Magnetic DB white dwarfs
  • 3.2. Stars with unidentifiable features
• 4. Final remarks
• Acknowledgements
• References

© European Southern Observatory (ESO) 1998

Online publication: August 6, 1998
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