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Daytona Beach


Physical Sciences

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We have extended our detailed survey of the local white dwarf population from 20 pc to 25 pc, effectively doubling the sample volume, which now includes 232 stars. In the process new stars within 20 pc have been added, a more uniform set of distance estimates as well as improved spectral and binary classifications are available. The present 25 pc sample is estimated to be about 68% complete (the corresponding 20 pc sample is now 86% complete). The space density of white dwarfs is unchanged at 4.8 ± 0.5 x 10-3 pc-3. This new study includes a white dwarf mass distribution and luminosity function based on the 232 stars in the 25 pc sample. We find a significant excess of single stars over systems containing one or more companions (74% vs 26%). This suggests mechanisms that result in the loss of companions during binary system evolution. In addition this updated sample exhibits a pronounced deficiency of nearby “Sirius-Like” systems. Eleven such systems were found within the 20 pc volume vs, only one additional system found in the volume between 20 pc and 25 pc. An estimate of white dwarf birth rates during the last ~ 8 Gyr is derived from individual remnant cooling ages. A discussion of likely ways new members of the local sample may be found is provided.

Publication Title

Monthly Notices of the Royal Astronomical Society



Oxford University Press

Additional Information

Dr. Oswalt was not affiliated with Embry-Riddle Aeronautical University at the time this paper was published.