Volume 546, October 2012
|Number of page(s)||12|
|Published online||12 October 2012|
Max-Planck Institute for Astrophysics,
Karl-Schwarzschild Str. 1,
2 Landessternwarte, Königstuhl 12, 69117 Heidelberg, Germany
3 Department of Physics, Western Michigan University, Kalamazoo, MI 49008, USA
Accepted: 5 July 2012
We investigate the statistical equilibrium of neutral and singly-ionized strontium in late-type stellar atmospheres. Particular attention is given to the completeness of the model atom, which includes new energy levels, transition probabilities, photoionization and electron-impact excitation cross-sections computed with the R-matrix method. The NLTE model is applied to the analysis of Sr I and Sr II lines in the spectra of the Sun, Procyon, Arcturus, and HD 122563, showing a significant improvement in the ionization balance compared to LTE line formation calculations, which predict abundance discrepancies of up to 0.5 dex. The solar Sr abundance is log ϵ = 2.93 ± 0.04 dex, in agreement with the meteorites. We present the grid of NLTE abundance corrections for Sr I and Sr II lines that covers a wide range of stellar parameters.
Key words: atomic data / line: formation / radiative transfer / Sun: abundances / stars: abundances / stars: atmospheres
Tables 3–5 are available in electronic form at http://www.aanda.org
The atomic data is available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (220.127.116.11) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/546/A90
© ESO, 2012
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