Discovery of Oxygen in the DQ White Dwarf Star G 227-5 (PG 1727+560): A Progress Report

Abstract

For many years it has been common knowledge that white dwarf stars have “carbon-oxygen” cores. But for equally many years, the ratio of carbon to oxygen in these cores has been essentially unknown. In recent years, the question of the interior chemical composition of white dwarf stars has become of interest for a variety of reasons that extend beyond our intrinsic interest in any accessible property of the stars which interests the community of people who do research on white dwarf stars:

The C₁₂> O₁₆reaction rate is coupled very sensitively to the bulk composition of white dwarf stars (Imbriani et al. 2003). The C/O ratio of white dwarf stars can also determine the chemical composition of the gas which low-mass stars recycle into the insterstellar medium, thus having an effect on galactic chemical evolution.