Spectroscopic confirmation of a white dwarf companion to the B star 16 Dra

Abstract

Using an Extreme Ultraviolet Explorer (EUVE) spectrum, we confirm the identification of a white dwarf companion to the B9.5V star 16 Dra (HD150100), and constrain its surface temperature to lie between 29,000K and 35,000K. This is the third B star + white dwarf non-interacting Sirius-type binary to be confirmed, after y Pup (HR2875, HD59635) and theta Hya (HR3665, HD79469). 16 Dra and its white dwarf companion are members of a larger resolved proper motion system including the B9V star 17 Dra A (HD150117). The white dwarf must have evolved from a progenitor more massive than this star, i.e. ~3.7 solar masses. White dwarf companions to B stars are important since they set an observational limit on the maximum mass for white dwarf progenitors, and can potentially be used to investigate the high mass ends of the initial-final mass relation and the white dwarf mass-radius relation.