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

D. Reimers; S. Jordan; V. Beckmann; N. Christlieb; L. Wisotzki

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

D. Reimers·S. Jordan·V. Beckmann·N. Christlieb·L. Wisotzki

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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 20MG, since the πcomponents of He I 5876 Angstroem and He I 4929 Angstroem can be identified unambiguously in their spectra, and the $σ^+$, $σ^-$ 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.

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D. Reimers, S. Jordan, V. Beckmann, N. Christlieb, L. Wisotzki. 1998-07-14. Four magnetic DB white dwarfs discovered by the Hamburg/ESO survey. https://arxiv.org/abs/astro-ph/9807135

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