A Census of White Dwarfs Within 40 Parsecs of the Sun

Abstract

Our aim is to compile a catalog of white dwarfs within 40 parsecs of the Sun, in which newly discovered objects would significantly increase the completeness of the current census. White dwarf candidates are identified from the SUPERBLINK proper motion database (Lepine & Shara 2005), which allows us to investigate stars down to a proper motion limit as low as 40 mas yr-1. The selection criteria and distance estimates are based on a combination of color-magnitude and reduced proper motion diagrams. Candidates with distances less than 50 parsecs are selected for spectroscopic follow-up. We present our preliminary sample of spectroscopically confirmed white dwarfs, as well as their atmospheric parameters. These parameters are obtained using the spectroscopic technique developed in Bergeron et al.(1992) for DA stars. DB, DQ, and DZ stars are also analyzed spectroscopically. For featureless spectra as well as those showing only Halpha, we perform a detailed photometric analysis of their energy distribution.Comment: 4 pages, 3 figures, to appear in AIP Conference Proceedings for the 17th European White Dwarf Worksho