Chemical Composition of the RS CVn-TYPE Star Lambda Andromedae

TL;DR

This study analyzes the chemical composition of the RS CVn-type star Lambda Andromedae, revealing elemental abundances and isotopic ratios, including the first determination of the 12C/13C ratio in such a star, suggesting active mixing processes.

Contribution

First measurement of the 12C/13C ratio in an RS CVn-type star, indicating possible extra-mixing in low-mass chromospherically active stars.

Findings

12C/13C ratio is 14, the first such measurement for this star type.

Detected elemental abundances suggest active mixing processes.

Provides insights into stellar evolution in active binary stars.

Abstract

Photospheric parameters and chemical composition are determined for the single-lined chromospherically active RS CVn-type star {\lambda} And (HD 222107). From the high resolution spectra obtained on the Nordic Optical Telescope, abundances of 22 chemical elements and isotopes, including such key elements as 12C, 13C, N and O, were investigated. The differential line analysis with the MARCS model atmospheres gives T eff=4830 K, log g=2.8, [Fe/H]=-0.53, [C/Fe]=0.09, [N/Fe]=0.35, [O/Fe]=0.45, C/N=2.21, 12C/13C = 14. The value of 12C/13C ratio for a star of the RS CVn-type is determined for the first time, and its low value gives a hint that extra-mixing processes may start acting in low-mass chromospherically active stars below the bump of the luminosity function of red giants.