Basic observational constraints on the evolution of massive stars

Abstract

The sources of information and uncertainties in the intrinsic stellar parameters of luminosity, effective temperature, mass, composition and mass loss rates are discussed. These are used to compare the observed positions of massive stars in the Hertzsprung-Russell Diagram (HRD) with evolutionary tracks. The current status of this effort is briefly reviewed. A short summary of the kinematic properties of massive stars is made. A preliminary but fairly extensive discussion of the distributions and numbers of O-type and Wolf-Rayet stars in the galaxy and other members of the local group is then given.