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

Using an Extreme Ultraviolet Explorer (EUVE) spectrum, we confirm the ident ification of a white dwarf companion to the B9.5V star 16 Dra (HD150100), a nd constrain its surface temperature to lie between 29,000 K and 35,000 K. This is the third B star + white dwarf non-interacting Sirius-type binary t o be confirmed, after y Pup (HR2875, HD59635) and theta Hya (HR3665, HD7946 9). 16 Dra and its white dwarf companion are members of a larger resolved p roper motion system including the B9V star 17 Dra A (HD150117). The white d warf must have evolved from a progenitor more massive than this star, M-MS approximate to 3.7M(circle dot). White dwarf companions to B stars are impo rtant since they set an observational limit on the maximum mass for white d warf progenitors, and can potentially be used to investigate the high mass ends of the initial-final mass relation and the white dwarf mass-radius rel ation.