3D-based solar/stellar abundance analyses
Martin Asplund

I will discuss current and future possibilities in terms of using realistic 3D radiative-hydrodynamical stellar atmosphere models for solar and stellar abundance analyses, including detailed non-LTE radiative transfer. Such modelling removes the free parameters (mixing length, micro- and macroturbulence) that have hampered stellar spectroscopy for many decades, which together with a more realistic atmosphere structure should lead to more reliable results in terms of inferred chemical compositions of stars. Recent work on 3D non-LTE modelling for the Sun and other stars have demonstrated the feasibility of this approach, which will be briefly discussed. The major challenge now is how to incorporate this much more computationally demanding stellar modelling for large-scale spectroscopic surveys involving thousands or even millions of stars.