Article révisé par les pairs
Résumé : Standard one-dimensional (1D) model atmospheres rely on the assumption of radiative equilibrium in the non-convective part of the stellar photosphere. However, gas-dynamical effects can lead to dramatic deviations from radiative equilibrium conditions, especially in metal-poor stellar atmospheres. These can be taken into account in 3D stellar atmosphere models representing the detailed interplay of hydrodynamics and radiation. During the last two years efforts have been invested to compute such 3D models for metal-poor atmospheres with the CO 5 BOLD code within the CIFIST (Cosmological Impact of the FIrst STars) Team, an European Union funded research group dedicated to the study of metal-poor stars. Based on the available models we will give an account of the radiation-hydrodynamical processes at work, and discuss consequences for the temperature scale and abundance analysis of metal-poor stars. © 2008 American Institute of Physics.