1999A&A...341..795B

We report the identification, in an Extreme Ultraviolet Explorer (EUVE) spectrum, of a hot white dwarf companion to the 3rd magnitude late-B star θ Hya (HR 3665, HD 79469). This is the second B star+white dwarf binary to be conclusively identified; Vennes et al. (1997ApJ...491L..85V), and Burleigh & Barstow (1998MNRAS.295L..15B) had previously reported the spectroscopic discovery of a hot white dwarf companion to the B5V star y Pup (HR 2875). Since these two degenerate stars must have evolved from main sequence progenitors more massive than their B star companions, they can be used to place observational lower limits on the maximum mass for white dwarf progenitors, and to investigate the upper end of the initial-final mass relation. Assuming a pure hydrogen composition, we constrain the temperature of the white dwarf companion to θ Hya to lie between 25,000K and 31,000K. We also predict that a third bright B star, 16 Dra (B9.5V), might also be hiding an unresolved hot white dwarf companion.