We have conducted a detailed new survey of the local population of white dwarfs lying within 20 pc of the Sun. A new revised catalog of local white dwarfs containing 122 entries (126 individual degenerate stars) is presented. This list contains 27 white dwarfs not included in a previous list from 2002, as well as new and recently published trigonometric parallaxes. In several cases new members of the local white dwarf population have come to light through accurate photometric distance estimates. In addition, a suspected new double degenerate system (WD 0423+120) has been identified. The 20 pc sample is currently estimated to be 80% complete. Using a variety of recent spectroscopic, photometric, and trigonometric distance determinations, we re-compute a space density of 4.8 ± 0.5 × 10 −3 pc −3 corresponding to a mass density of 3.2 ± 0.3 × 10 −3 M pc −3 from the complete portion of the sample within 13 pc. We find an overall mean mass for the local white dwarfs of 0.665 M , a value larger than most other non-volume-limited estimates. Although the sample is small, we find no evidence of a correlation between mass and temperature in which white dwarfs below 13,000 K are systematically more massive than those above this temperature. Within 20 pc 25% of the white dwarfs are in binary systems (including double degenerate systems). Approximately 6% are double degenerates and 6.5% are Sirius-like systems. The fraction of magnetic white dwarfs in the local population is found to be 13%.
The most recent version of the Catalog of Spectroscopically Identified White
Dwarfs lists 2249 white dwarf stars. Among these stars are 118 white dwarfs
that have either reliable trigonometric parallaxes or color-based distance
moduli which place them at a distance within 20 pc of the Sun. Most of these
nearby white dwarfs are isolated stars, but 35 (30 % of the sample) are in
binary systems, including such well known systems as Sirius A/B, and Procyon
A/B. There are also three double degenerate systems in this sample of the local
white dwarf population. The sample of local white dwarfs is largely complete
out to 13 pc and the local density of white dwarf stars is found to be (5.5 +/-
0.8) x 10^-3 pc^-3 with a corresponding mass density of (3.7 +/- 0.5) x10^-3 M
pc^-3.Comment: 20 pages, 3 Postscript figure
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