Hostname: page-component-7bb8b95d7b-nptnm Total loading time: 0 Render date: 2024-09-21T07:54:33.832Z Has data issue: false hasContentIssue false

Contribution of White Dwarfs to Cluster Masses

Published online by Cambridge University Press:  14 August 2015

Ted Von Hippel*
Affiliation:
Department of Astronomy University of Wisconsin Madison, WI 53706, USAted@noao.edu

Extract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

The study of cluster white dwarfs (WDs) has been invigorated recently bythe Hubble Space Telescope (HST). Recent WD studies have been motivated by the new and independent cluster distance (Renzini et al. 1996), age (von Hippel et al. 1995; Richer et al. 1997), and stellar evolution (Koester & Reimers 1996) information that cluster WDs can provide. An important byproduct of these studies has been an estimate of the WD mass contribution in open and globular clusters. The cluster WD mass fraction is of importance for understanding the dynamical state and history of star clusters. It also bears an important connection to the WD mass fractions of the Galactic disk and halo. Current evidence indicates that the open clusters (e.g. von Hippel et al. 1996; Reid this volume) have essentially the same luminosity function (LF) as the solar neighborhood population. The case for the halo is less clear, despite the number of very good globular cluster LFs down to nearly 0.1 solar masses (e.g. Cool et al. 1996; Piotto, this volume), as the field halo LF is poorly known. For most clusters dynamical evolution should cause evaporation of the lowest mass members, biasing clusters to have flatter present-day mass functions (PDMFs) than the disk and halo field populations. Dynamical evolution should also allow cluster WDs to escape, though not in the same numbers as the much lower mass main sequence stars. The detailed connection between cluster PDMFs and the field IMF awaits elucidation from observations and the new combined N-body and stellar evolution models (Tout, this volume). Nevertheless, the WD mass fraction of clusters already provides an estimate for the WD mass fraction of the disk and halo field populations. A literature search to collect cluster WDs and a simple interpretive model follow. This is a work in progress and the full details of the literature search and the model will be published elsewhere.

Type
II. Joint Discussions
Copyright
Copyright © Kluwer 1998

References

Boehm-Vitense, E. 1993, AJ, 106, 1113 Google Scholar
Chaboyer, B., Demarque, P., Kernan, P.J., & Krauss, L.M. 1997, ApJ, in pressGoogle Scholar
Cool, A.M., Piotto, G., & King, I.R. 1996, ApJ, 468, 655 Google Scholar
Eggleton, P.P., Fitchett, M.J., & Tout, C.A. 1989, ApJ, 347, 998 Google Scholar
Koester, D., & Reimers, D. 1996, A&A, 313, 810 Google Scholar
Reid, N. 1992, MNRAS, 257, 257 Google Scholar
Renzini, A., et al. 1996, ApJ, 465, L23 Google Scholar
Richer, H.B., et al. 1995, ApJ, 451, L17 Google Scholar
Richer, H.B., et al. 1997, ApJ, 484, 741 Google Scholar
Sigurdsson, S. 1993, ApJ, 415, L43 Google Scholar
von Hippel, T., Bothun, G.D., & Schommer, R.A. 1997, AJ, 114, 1154 Google Scholar
von Hippel, T., et al. 1996, AJ, 112, 192 Google Scholar
von Hippel, T., Gilmore, G., & Jones, D.H.P. 1995, MNRAS, 273, L39 Google Scholar
Weidemann, V., Jordan, S., Iben, I., & Casertano, S. 1992, AJ, 104, 1876 Google Scholar
Weidemann, V., & Koester, D. 1983, A&A, 121, 77 Google Scholar
Wegner, G., Reid, I.N., & McMahan, R.K. 1989, in White Dwarfs, ed. Wegner, G., (Springer-Verlag: Berlin), 378 Google Scholar
White, S.M., Jackson, P.D., & Kundu, M.R. 1993, AJ, 105, 563 Google Scholar