Abstract

Photometric and spectroscopic modelling of warm DQ stars.

Alexandre Fortier (Université de Montréal)

Patrick Dufour, Université de Montréal

The "Hot DQ" white dwarfs, a new class of stars showing a surface composition dominated by carbon (Dufour et al. 2007), represent a challenge to stellar evolution. Little is known on how exactly they form or evolve. The first few stars discovered in the SDSS survey were all found in a narrow range of effective temperature (18,000-24,000 K). It has been suggested at the last workshop that these stars may evolve into warm (Teff = 12,000-18,000 K) and highly polluted (log C/He > -3.0) DQ white dwarfs with atomic CI lines. We present an analysis of a sample of such warm DQ white dwarfs, filling the gap between the Hot DQ and the cooler DQ with molecular bands.

Mode of presentation: poster