The Influence of WR Like Stellar Wind Mass Loss Rates on the Evolution of Massive Core Helium Burning Stars

Extract

Evolutionary computations of massive close binaries (MCB) including the effects of stellar wind (SW) and convective core overshooting predict that all massive primaries with ZAMS mass larger than 10 M_⊙ start their core helium burning phase (CHeB) as bare helium cores; the hydrogen rich layers are removed on a timescale of the order of 10⁴ yrs as a consequence of Roche lobe overflow (RLOF). The CHeB remnant after RLOF resembles closely a zero age CHeB star and its further evolution is entirely independent from its binary nature. Similarly as has been done previously by Vanbeveren and Packet (1979, A.&A.80, 242), I have performed a phenomenological study on the evolution of massive hydrogen less CHeB stars including the effect of SW mass loss using updated M determinations of van der Hucht et al. (1986, A.&A.168, 111). The SW mass loss rate formalism used in the computations is based on the following requirements: