A non-LTE study of silicon abundances in giant stars from the Si I infrared lines in the zJ-band

We investigate the feasibility of the Si I infrared (IR) lines as Si abundance indicators for giant stars. We find that Si abundances obtained from the Si I IR lines based on the local thermodynamic equilibrium (LTE) analysis show large line-to-line scatter (mean value of 0.13dex), and are higher th...

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Published inarXiv.org
Main Authors Tan, Kefeng, Shi, Jianrong, Takada-Hidai, Masahide, Takeda, Yoichi, Zhao, Gang
Format Paper Journal Article
LanguageEnglish
Published Ithaca Cornell University Library, arXiv.org 21.03.2016
Subjects
Giant stars
Indicators
Local thermodynamic equilibrium
Physics - Solar and Stellar Astrophysics
Scattering
Silicon
Stars
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Summary:We investigate the feasibility of the Si I infrared (IR) lines as Si abundance indicators for giant stars. We find that Si abundances obtained from the Si I IR lines based on the local thermodynamic equilibrium (LTE) analysis show large line-to-line scatter (mean value of 0.13dex), and are higher than those from the optical lines. However, when the non-LTE effects are taken into account, the line-to-line scatter reduces significantly (mean value of 0.06dex), and the Si abundances are consistent with those from the optical lines. The typical average non-LTE correction of [Si/Fe] for our sample stars is about \(-\)0.35dex. Our results demonstrate that the Si I IR lines could be reliable abundance indicators provided that the non-LTE effects are properly taken into account.
ISSN:2331-8422
DOI:10.48550/arxiv.1603.06305