Abstract

Physical properties of the current census of white dwarfs within 40 pc of the Sun

Marie-Michèle Limoges (Université de Montréal)

Pierre Bergeron (Université de Montréal) & Sébastien Lépine (Georgia State University)

The large spectroscopic survey undertaken several years ago based on the SUPERBLINK database led to the identification of 322 new white dwarfs, among which 173 lie within 40 pc of the Sun. Based on the white dwarf space density at 13 pc, we estimate the completeness of our survey between 63 and 73%, allowing for uncertainties in the distance estimates. Our method for selecting white dwarf candidates from the SUPERBLINK catalog is based on a combination of theoretical color-magnitude relations and reduced proper motion diagrams. After performing a homogeneous model atmosphere analysis of this 40 pc sample, we find a large fraction of massive white dwarfs, indicating that we are successfully recovering the more massive, and less luminous objects often missed in other surveys. We also show that the 40 pc sample is dominated by cool and old white dwarfs, which populate the faint end of the luminosity function. Finally, we identify 4 probable members of the 20 pc sample and we report the discovery of a new ZZ Ceti pulsator.

Mode of presentation: oral