Radiation driven winds from hot stars: hydrodynamic models with detailed non-LTE radiative transfer

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Stars much more massive than the sun play an important role in the cosmic evolution. As their special property, they possess stellar winds that blow lots of matter into their environment. Radiation pressure must be considered in the first place as the driving mechanism. While this is reasonably well understood for part of the stars, the models fail just for the strongest of those stellar winds, which emerge from the so-called Wolf-Rayet stars. After pilot studies we can assume that those strong winds can also be explained by radiation pressure. If so, the corresponding shortfall of previous hydrodynamical models must be due to certain approximations in their treatment of radiative transfer.Such simplifications are avoided by the Potsdam Wolf-Rayet (PoWR) model atmosphere code, which we have developed for the simulation and analysis of spectra. As we have already shown, this code can be combined with the hydrodynamic equations. In the proposed project we will develop these model calculation into a form that they can be routinely applied. Then the comparison with observations will reveal if the dense stellar winds can be generally explained by radiation pressure. The final goal are realistic model predictions, which are needed for understanding the evolution of massive stars and the cosmic circuit of matter.