EXTRAGALACTIC STELLAR ASTRONOMY WITH BLUE SUPERGIANTS

The present generation of large telescopes facilitates spectroscopy of blue supergiants in galaxies out to distances beyond the Local Group. Recent developments in NLTE spectrum synthesis techniques allow for an accurate determination of stellar parameters and chemical abundances. Quantitative analyses of blue supergiants in different galactic environments can provide tight observational constraints on: i) the evolution of massive stars over a wide range of metallicities, ii) the chemical evolution of different galaxy types, using stars as tracers of abundance gradients, iii) the extragalactic distance scale. The current status of the field is summarised.