Contribution of White Dwarfs to Cluster Masses

I present a literature search through 31 July 1997 of white dwarfs (WDs) inopen and globular clusters. There are 36 single WDs and 5 WDs in binaries knownamong 13 open clusters, and 340 single WDs and 11 WDs in binaries known among11 globular clusters. From these data I have calculated WD mass fractions forfour open clusters (the Pleiades, NGC 2168, NGC 3532, and the Hyades) and oneglobular cluster (NGC 6121). I develop a simple model of cluster evolution thatincorporates stellar evolution but not dynamical evolution to interpret the WDmass fractions. I augment the results of my simple model with N-bodysimulations incorporating stellar evolution (Terlevich 1987; de la FeunteMarcos 1996; Vesperini & Heggie 1997). I find that even though these clustersundergo moderate to strong kinematical evolution the WD mass fraction isrelatively insensitive to kinematical evolution. By comparing the cluster massfunctions to that of the Galactic disk, and incorporating plausibilityarguments for the mass function of the Galactic halo, I estimate the WD massfraction in these two populations. I assume the Galactic disk is ~10 Gyrs old(Winget et al. 1987; Liebert, Dahn, & Monet 1988; Oswalt et al. 1996) and thatthe Galactic halo is ~12 Gyrs old (Reid 1997b; Gratton et al. 1997; Chaboyer etal. 1998), although the WD mass fraction is insensitive to age in this range. Ifind that the Galactic halo should contain 8 to 9% (alpha = -2.35) or perhapsas much as 15 to 17% (alpha = -2.0) of its stellar mass in the form of WDs. TheGalactic disk WD mass fraction should be 6 to 7% (alpha = -2.35), consistentwith the empirical estimates of 3 to 7% (Liebert, Dahn, & Monet 1988; Oswalt etal. 1996). (abridged)Comment: 20 pages, uuencoded gunzip'ed latex + 3 postscrip figures, to be published in AJ, April, 199