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Extending the White Dwarf Sequence: Plans and Prospects

Published online by Cambridge University Press:  14 August 2015

James Liebert
James Liebert*
Affiliation:
Steward Observatory, University of Arizona

Extract

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The recent discovery that the parallax star LP701-29 is a white dwarf has firmly extended the degenerate sequence below MV = +16m (Dahn et al. 1978). As the search for white dwarfs extends to cooler and fainter stars, however, it becomes particularly important to develop a plan for selecting candidates among the many thousands of red proper motion stars. We begin by assessing the completeness of the known sample within 10 parsecs in the northern two thirds of the sky. Some color-dependent selection effects must be evaluated, however, since these may preferentially inhibit the discovery of cooler stars. A correction factor for the missing low velocity white dwarfs is estimated. Then, Green's(1977) recent determination of the number density of blue degenerates is used to normalize various theoretical luminosity functions, the benchmarks against which the current sample out to 10 pc can be compared. It is concluded that the sample may be approaching completeness in the northern sky for white dwarfs with tangential velocities (vT) ≥ 40 km/sec (μ ≥ 1″.0/yr.) and Mbol < +15m. The implied luminosity function is thus consistent with that found by Sion and Liebert (1977). Below Mbol = +15m the different theoretical functions predict substantially different numbers.

Type
Poster Session
Information
Symposium - International Astronomical Union , Volume 80: The HR Diagram , 1978 , pp. 437 - 440
Copyright
Copyright © Reidel 1978 

References

Dahn, C., Hintzen, P., Liebert, J., Stockman, H. and Spinrad, H. (1978). Astrophys. J., in press.Google Scholar
Green, R. (1977). , California Institute of Technology.Google Scholar
Lamb, D.Q., and Van Horn, H.M. (1975). Astrophys. J., 200, 306.CrossRefGoogle Scholar
Liebert, J. (1978). in preparation.Google Scholar
Liebert, J., and Strittmatter, P. (1978). in preparation.Google Scholar
Shaviv, G., and Kovetz, A. (1976). Astron. Astrophys., 51, 383.Google Scholar
Sion, E., and Liebert, J. (1977). Astrophys. J., 213, 468.CrossRefGoogle Scholar
Sweeney, M. (1976). Astron. Astrophys., 49, 375.Google Scholar
Wielen, R. (1974). in Highlights of Astronomy, 3, ed. Contopoulos, G., D. Reidel Publishing Co., Dordrecht, Holland, p. 395.CrossRefGoogle Scholar