Identification of a DO White Dwarf and a PG1159 Star in the ESO SN Ia Progenitor Survey (SPY)

摘要

We present high-resolution VLT spectra of a new DO white dwarf and a new PG1159 star, which we identified in the ESO SPY survey. The PG1159 star is a low-gravity, extremely hot star, having a C/He dominated atmosphere with considerable amounts of O and Ne. It is located within the planetary nebula nuclei instability strip and pulsations have been discovered. The DO is a unique object. From He I/He II line strengths we found T-(eff)60000K, however, the He II lines are extraordinarily strong and cannot be fitted by any model.