Impact of NLTE on determinations of atmospheric parameters and chemical abundances of very metal-poor stars
نویسندگان
چکیده
منابع مشابه
Abundances in Very Metal-Poor Stars
Metal-poor stars provide information on the characteristics and chemical evolution of the halo population of the Galaxy, the first epoch of star formation and Galaxy formation (not just locally but with relevance to high-redshift objects), and big bang nucleosynthesis. This review looks at recent developments in this subject.
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NLTE abundances of Mn in a sample of metal-poor stars
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 NL...
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Europium isotopic abundance fractions are reported for the very metal-poor, neutron-capture-rich giant stars CS 22892-052, HD 115444, and BD +17◦3248. The abundance fractions, derived from analysis of several strong Eu II lines appearing in high-resolution spectra of these stars, are in excellent agreement with each other and with their values in the Solar System: fr(Eu)≃ fr(Eu) ≃ 0.5. Detailed...
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ژورنال
عنوان ژورنال: Proceedings of the International Astronomical Union
سال: 2017
ISSN: 1743-9213,1743-9221
DOI: 10.1017/s1743921317006962