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

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.

arXiv comment4 pages, 2 figures, accepted for publication in A&A Letters

References in corpus (4)

• The Sloan Digital Sky Survey: Technical Summary
• A Catalog of Spectroscopically Identified White Dwarf Stars in the First Data Release of the Sloan Digital Sky Survey
• An Initial Survey of White Dwarfs in the Sloan Digital Sky Survey
• A First Look at White Dwarf - M Dwarf Pairs in the Sloan Digital Sky Survey (SDSS)

Cited by in corpus (6)

• Post-common envelope binaries from SDSS - VII: A catalogue of white dwarf-main sequence binaries
• New Close Binary Systems from the SDSS-I (Data Release Five) and the Search for Magnetic White Dwarfs in Cataclysmic Variable Progenitor Systems
• White Dwarf - Red Dwarf Systems Resolved with the Hubble Space Telescope: I. First Results
• Post common envelope binaries from SDSS. II: Identification of 9 close binaries with VLT/FORS2
• White dwarf-main sequence binaries from LAMOST: the DR1 catalogue
• Astrophysics in 2005