Published online by Cambridge University Press: 08 March 2006
Red Supergiant (RSG) represent a key-phase in the evolution of massive stars. These stars are characterized by strong mass loss of unknown origin. Observations show strong line profile fluctuations in depth, width and velocity, suggesting giant convective cells which could explain mass loss.Recently, radiative hydrodynamics (RHD) simulations of these stars show a peculiar convection pattern with giant cells. We performed 3D pure LTE radiative transfer calculations in snapshots of 3D hydrodynamical simulations taking into account the Doppler shifts caused by the convective motions. Computed spectra from RHD models qualitatively reproduce observations.