scholarly journals Concerning the Li-rich status of KIC 9821622: a Kepler field RGB star reported as a Li-rich giant

2019 ◽  
Vol 491 (3) ◽  
pp. 3838-3843
Author(s):  
Raghubar Singh ◽  
Yerra Bharat Kumar ◽  
Bacham E Reddy ◽  
Wako Aoki

ABSTRACT Given the implications for the origin of Li enhancement in red giants, we have reviewed the Li-rich classification of KIC 9821622, the only bonafide red giant branch (RGB) giant with a He inert core to date, reported as a Li-rich giant by reanalysing the high-resolution spectra. We have obtained A(Li)LTE = 1.42 ± 0.05 dex. After correcting for non-local thermodynamic equilibrium (NLTE), we have A(Li)NLTE = 1.57 ± 0.05 dex, which is significantly less than the reported A(Li) = 1.80 ± 0.2 dex. We found that the subordinate line at 6103 Å is too weak or absent to measure Li abundance. The derived abundance is normal for red giants undergoing dilution during the first dredge-up. Since all known Kepler field Li-rich giants belong to the red clump region, this clarification removes the anomaly and strengthens the evidence that Li enhancement in low-mass giants may be associated only with the He-core burning phase. The origin of Li excess probably lies during the He flash at the RGB tip, a phase immediately preceding the red clump.

2013 ◽  
Vol 82 (2) ◽  
pp. 024501
Author(s):  
Xiao-Ying Han ◽  
Fei-Lu Wang ◽  
Ze-Qing Wu ◽  
Jun Yan ◽  
Gang Zhao

1987 ◽  
Vol 120 ◽  
pp. 583-598
Author(s):  
David L. Lambert

A general review is given of the astrophysical information obtainable from observations of molecules in stellar photospheres. Through selected examples, the use of molecules as thermometers (e.g., the OH 3 μm V-R lines in the Sun and α Ori) and as probes of the isotopic (e.g., iMg in metal-poor dwarfs, 12C/13C in cool carbon stars) and elemental abundances (e.g., CNO in red giants) is sketched. All of the (carefully) selected analyses assume that local thermodynamic equilibrium (LTE) prevails.


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