NLTE abundances of Mn in a sample of metal-poor stars
Abstract
Aims: Following our solar work, we perform NLTE calculations of the Mn abundance for fourteen stars with [Fe/H] from 0 to -2.5, mainly to show how NLTE affects Mn abundances in cool stars of different metallicities.
Methods: The spectrum synthesis and Mn abundances are based on statistical equilibrium calculations using various estimates for the influence of hydrogen collisions.
Results: The NLTE abundances of Mn in all studied stars are systematically higher than the LTE abundances. At low metallicities, the NLTE abundance corrections may run up to 0.5-0.7 dex. Instead of a strong depletion of Mn relative to Fe in metal-poor stars as found by the other authors, we only find slightly subsolar values of [Mn/Fe] throughout the range of metallicities analyzed here.
Conclusions: The [Mn/Fe] trend in metal-poor stars is inconsistent with the predictions of galactic chemical evolution models, where Mn is less produced than Fe.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- December 2008
- DOI:
- 10.1051/0004-6361:200810098
- arXiv:
- arXiv:0811.0681
- Bibcode:
- 2008A&A...492..823B
- Keywords:
-
- line: profiles;
- line: formation;
- stars: abundances;
- nuclear reactions;
- nucleosynthesis;
- abundances;
- Astrophysics
- E-Print:
- A&