Atomic diffusion across the HR diagram

International audienceIt is clear that in order to explain many observed stellar phenomena, atomic diffusion must be included in stellar models. The effects of atomic diffusion are not limited to the surface abundances as we will see, it occurs in stars from the surface to the center and even if these effects are reduced in the external layers by other transport processes it remains in the center. We will also see that the induced chemical stratification has a strong impact on the stellar opacity