Wolf-Rayet Stars in Galaxies and the Role of Binaries and Hydrodynamics

摘要: WR stars obey M—L—Ṁ—T eff —R—chemistry relations, which are in general model independent (with the exception of chemistry). The processes formation (stellar winds, hydrodynarnical mixing, binary mass transfer etc.) influence, however, domain parameters occupied by stars. We specifically examine distribution luminosities and H—contents WN stars, both support heavy loss rates, or possibly main sequence WNL phases. Detailed studies number ratios WR/O, WC/WN, WC/WR, etc. made for galaxies at various metallicities Z exhibit extremely different populations. Good agreement models observations is found. It also shown that data better explained if a certain fraction ϕ (less than 10%) O—stars become preferentially type WNE as result Roche lobe overflow (RLOF) binaries. This necessarily implies owing their existence to RLOF, variable with Z, being nearly 100% low much smaller high Z. identify several hydrodynamical developments physically required stellar models. Among them, we collect available observational theoretical arguments supporting an important role mixing massive star evolution.