The Effect of Scattering on the Temperature Stratification of 3D Model Atmospheres of Metal-Poor Red Giants

We study the effects of different approximations of scattering in 3D radiationhydrodynamics simulations on the photospheric temperature stratification of metal-poor red giant stars. We find that assuming a Planckian source function and neglecting the contribution of scattering to extinction in optically thin layers provides a good approximation of the effects of coherent scattering on the photospheric temperature balance.