The effect of micro-turbulence in O-type star analyses

We study here the influence of micro-turbulence in the synthesis of H and He lines, in order to quantify its effect on the determination of stellar parameters of O-type stars, in particular on the stellar He abundance. We find that only He I lines and He II lambda 4686 are considerably affected, the effect being more relevant for models corresponding to supergiant stars. We also find that neglecting micro-turbulence in the analyses of O-type stars introduces deviations in the derived parameters that are within our standard error box. The He content is not or slightly reduced, thus micro-turbulence cannot be responsible for the He-discrepancy to all its extent.