The interplay of mass loss and core overshooting in massive stars

In this study analytic models are used in an attempt to constrain the overshooting parameter in massive stars. It is found that core overshooting up to of order 20% is required to explain the non-existence of red supergiants withM _bol<–10. Furthermore, a critical mass of 60M marks the upper mass limit for stars that can undergo a red supergiant phase. The analysis employed clearly demonstrates an important interplay between mass loss and core overhooting-highlighting the difficulty of establishing the uniqueness of a given set of results.