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Session 79 - White Dwarf Stars.
Display session, Wednesday, January 15
Metropolitan Ballroom,

[79.05] The White Dwarf Luminosity Function and the Age of the Galaxy

J. A. Smith (U. Michigan), T. D. Oswalt (Florida Tech)

We present the results for the White Dwarf Luminosity Function (WDLF) derived from our entire sample of common proper motion binaries (CPMBs) containing white dwarfs (WDs). Approximately 170 WDs are contained in our study which makes it one of the largest samples ever used in the determination of the WDLF. We will discuss our sample selection and completion techniques and the constraint this sample places on the debate about the age of the Galaxy and ultimately the Universe.

The WDs in this study were identified spectroscopically [Oswalt et al. in White Dwarfs, ed. G. Wegner, (Springer: Berlin), (1990)] and satisfy the limits [V < 18.50, \mu > 0.10 "/yr] over which the sample's incompleteness is well-behaved (and hence correctible). The size of this sample allows us to set firm limits on the age of Galactic disk, making use of the latest interior [Wood, in White Dwarfs, eds. D. Koester amp; K. Werner (Kluwer: Dordrecht), 1995] and atmosphere [Bergeron, P., et al. Astrophys. J. 449, 258-279, 1995] models. Our new results, which strengthen the \ge 9.5^+1.1_-0.8 Gyr(1 \sigma) age for the Galactic disk [Oswalt et al. Nature 382, 692 (1996)], will be presented.

JAS gratefully acknowledges support from the NASA Graduate Student Researchers Program, grant NGT-51086 and TDO gratefully acknowledges support from NSF grant AST 90-16284.

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