New neon-abundance results in Galactic WN and WC stars

Abstract

The fast, dense winds which characterize Wolf-Rayet stars obscure their underlying cores, and complicate the verification of evolving core and nucleosynthesis models. A powerful technique for probing WR core evolution involves measuring abundances of wind-borne nuclear processed elements. Neon, in particular, undergoes a remarkable change in abundance during the later stages of a WR star's lifetime. By the end of the WC phase, it becomes the fourth most abundant element, after He, C and O (Maeder 1983).