A CCD Survey For Old White Dwarf Stars

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Because the cooling times for white dwarfs are very long, the oldest stars in the galaxy have not yet faded below detection limits. Thus, the white dwarf luminosity function should show a sudden drop-off below the luminosity they could have reached in the age of the population from which they evolved. This fact can be used to determine that age. Unfortunately, the stars in question are faint and the numbers found in the galactic disk are too small to provide a good statistical sample. Few, if any, are known in the halo. A CCD camera on the McDonald Observatory 30 inch telescope in Texas will be employed to search for cool, faint white dwarfs in both the disk population and the halo. This will increase greatly the sample of such stars known and will make them much more useful for studying the star formation history and age of the populations they represent.