Atmospheric Lithium Abundances of the Carbon Giants AQ And, HK Lyr, UX Dra, and WZ Cas

作者：Yakovina L A^*; Pavlenko Ya V

来源：Astronomy Reports, 2012, 56(1): 63-76.

DOI：10.1134/S1063772912010106

The LTE lithium abundances, log N (Li), have been determined for the atmospheres of the four carbon giants AQ And, HK Lyr, UX Dra, and WZ Cas, applying the synthetic-spectrum technique to the LiI lambda 670.8 nm resonance doublet. We used estimates of the effective temperatures T-eff, metallicities, elemental abundances, and carbon-isotope ratios for these stars from the literature [12C/13C]. The resulting lithium abundances depend significantly on the adopted T-eff, so that we can find each star's range of possible logN(Li) values for a given range of effective temperatures (Delta T-eff = 200-300 K). The uncertainty in the derived log N(Li) values is 1.3 for AQ And and UX Dra, 0.5 for HK Lyr, and 0.8 for WZ Cas. Our most probable logN(Li) values (or ranges) are -1.25 for AQ And, -1.2 for HK Lyr, -1.0 <= logN(Li) <= + 0.3 for UX Dra, and 4.3 <= logN(Li) <= 4.8 for WZ Cas. The derived C/O ratios for the stellar atmospheres also depend on T-eff. Possible uncertainties in other atmospheric parameters do not change logN(Li) by more than 0.2. DOI: 10.1134/S1063772912010106

• 出版日期2012-1