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Identification of 13 DB + dM and 2 DC + dM binaries from the Sloan Digital Sky Survey

E. J. M. van den Besselaar·G. H. A. Roelofs·G. A. Nelemans·T. Augusteijn·P. J. Groot
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Abstract

We present the identification of 13 DB + dM binaries and 2 DC + dM binaries from the Sloan Digital Sky Survey (SDSS). Before the SDSS only 2 DB + dM binaries and 1 DC + dM binary were known. At least three, possibly 8, of the new DB + dM binaries seem to have white dwarf temperatures well above 30000 K which would place them in the so called DB-gap. Finding these DB white dwarfs in binaries may suggest that they have formed through a different evolutionary channel than the ones in which DA white dwarfs transform into DB white dwarfs due to convection in the upper layers.

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E. J. M. van den Besselaar, G. H. A. Roelofs, G. A. Nelemans, T. Augusteijn, P. J. Groot. 2005-03-23. Identification of 13 DB + dM and 2 DC + dM binaries from the Sloan Digital Sky Survey. https://doi.org/10.1051/0004-6361%3A200500102

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