Details

Autor(en) / Beteiligte

• Lind, K.
• Amarsi, A. M.
• Asplund, M.
• Barklem, P. S.
• Bautista, M.
• Bergemann, M.
• Collet, R.
• Kiselman, D.
• Leenaarts, J.
• Pereira, T. M. D.

Titel

Non-LTE line formation of Fe in late-type stars – IV. Modelling of the solar centre-to-limb variation in 3D

Ist Teil von

• Monthly notices of the Royal Astronomical Society, 2017, Vol.468 (4), p.4311-4322

Ort / Verlag

Oxford University Press

Erscheinungsjahr

2017

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Abstract Our ability to model the shapes and strengths of iron lines in the solar spectrum is a critical test of the accuracy of the solar iron abundance, which sets the absolute zero-point of all stellar metallicities. We use an extensive 463-level Fe atom with new photoionization cross-sections for Fe i and quantum mechanical calculations of collisional excitation and charge transfer with neutral hydrogen; the latter effectively remove a free parameter that has hampered all previous line formation studies of Fe in non-local thermodynamic equilibrium (NLTE). For the first time, we use realistic 3D NLTE calculations of Fe for a quantitative comparison to solar observations. We confront our theoretical line profiles with observations taken at different viewing angles across the solar disc with the Swedish 1-m Solar Telescope. We find that 3D modelling well reproduces the observed centre-to-limb behaviour of spectral lines overall, but highlight aspects that may require further work, especially cross-sections for inelastic collisions with electrons. Our inferred solar iron abundance is log (εFe) = 7.48 ± 0.04 dex.