White Dwarfs in Open Clusters

University Of California-Santa Cruz, Santa Cruz CA

Investigators

Abstract

AST 0307492 Bolte, Michael J. The investigators in this project are carrying out an extensive search for white dwarf stars in young open clusters with the primary goal to identify the main sequence stellar mass above which stars explode as core collapse supernovae and below which stars end their lives as white dwarfs. The value for this critical mass is important in a wide range of areas. The number of core-collapse supernovae in a stellar population has important implications for chemical enrichment and energy balance in galaxies. Supernovae kinetic energy feedback may be the dominant process in the early evolution of dwarf galaxies and is an important mechanism for regulating star formation in young galaxies of all masses. The current uncertainty in the value of the critical mass is large with values in the recent literature ranging from 5 to 8 solar masses. Identifying the critical mass for the formation of white dwarfs is also important for providing constraints on physical processes in giant stars that lead to the formation and growth of the core that eventually becomes the white dwarf remnant. A valuable side benefit of this program is improved estimates of the ages, distances and initial mass functions of a number of young and intermediate-age open clusters. Broader Impact. The researchers are making their data and analysis tools available freely at a WWW site during the course of the work. Astronomy and physics graduate and undergraduate students are involved in the research.