SIMBAD references

Photospheric parameters and chemical composition are determined for the single-lined chromospherically active RS CVn-type star 29 Draconis (HD 160538). From the high resolution spectra obtained on the Nordic Optical Telescope, abundances of 22 chemical elements, including the key elements such as ¹²C, ¹³C, N and O, were investigated. The differential line analysis with the MARCS model atmospheres gives T_eff = 4720 K, log g = 2.5, [Fe/H] = -0.20, [C/Fe] = -0.14, [N/Fe] = 0.08, [O/Fe] = -0.04, C/N = 2.40, ¹²C/¹³C = 16. The low value of the ¹²C/¹³C ratio gives a hint that extra mixing processes in low-mass chromospherically active stars may start earlier than the theory of stellar evolution predicts.