A NON-LTE STUDY OF SILICON ABUNDANCES IN GIANT STARS FROM THE Si i INFRARED LINES IN THE zJ -BAND

Journal Article · Fri May 20 04:00:00 EDT 2016 · Astrophysical Journal

DOI:https://doi.org/10.3847/0004-637X/823/1/36· OSTI ID:22666264

Tan, Kefeng; Shi, Jianrong; Zhao, Gang ^[1]; Takada-Hidai, Masahide ^[2]; Takeda, Yoichi ^[3]

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1. Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China)
2. Liberal Arts Education Center, Tokai University, 4-1-1 Kitakaname, Hiratsuka, Kanagawa 259-1292 (Japan)
3. National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)

We investigate the feasibility of 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 0.13 dex), and are higher than those from the optical lines. However, when non-LTE effects are taken into account, the line-to-line scatter reduces significantly (mean value of 0.06 dex), 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 −0.35 dex. 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.

• OSTI ID: 22666264
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 823; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ABUNDANCE
ATMOSPHERES
CORRECTIONS
GALAXIES
GIANT STARS
INFRARED SPECTRA
LTE
SILICON
STAR EVOLUTION
THERMODYNAMICS