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A new era for stellar abundances: non-LTE and 3D spectral line formation

Damian Fabbian
Instituto de Astrofisica de Canarias

In this talk I will present theoretical results on non-local Thermodynamic Equilibrium (non-LTE) spectral line formation in late-type stars obtained using the statistical equilibrium code MULTI. Neutral carbon and oxygen permitted lines of common use in stellar abundance studies have in particular been targetted. The results of the improved analysis (compared to standard modelling) show a large impact, in the sense of negative abundance corrections of up to several tenths of a dex at the lowest metallicities explored ([Fe/H]~-3). I will discuss the implications in terms of Galactic Chemical Evolution, as traced by the abundance ratios of these elements.

My work on supercomputer MHD simulations of stellar atmospheres - recently started within the EU solar physics SOLAIRE network, and using the Copenhagen group stagger-code - will also be quickly described, with an eye on its objectives and on possible implications of the planned research. Applying these state-of-the-art tools, stellar chemical abundance studies on existing (and currently planned large-scale) facilities will benefit from the improved precision in the derivation of the composition of stars.

2009 January 28, 13:30

Centro de AstrofÝsica da Universidade do Porto (Auditorium)
Rua das Estrelas, 4150-762 Porto

Instituto de Astrof├şsica e Ci├¬ncias do Espa├žo Universidade do Porto Faculdade de Ciências da Universidade de Lisboa Funda├ž├úo para a Ci├¬ncia e a Tecnologia
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