The Li, C, N, O abundances and the 12C/13C isotopic ratio in the atmospheres of the K giants 39 CYG and alpha Ari.

For two K giants, 39 Cyg (K3 III), a star with an intense Li I 6708 A line, and Ari (K2 III), with a weak Li I line typical of K giants, the Li, C, N, and O abundances and C-12/C-13 isotopic ratios were determined by the synthetic-spectrum method based on model stellar atmospheres. The observations of selected spectral regions were carried out with a CCD matrix mounted in the coude focus of the 2.5-m telescope of the Crimean Astrophysical Observatory (spectral resolution about 0.2 A). Possible causes of the enhanced Li abundance of +1.15 dex, and of the lowered value of the isotopic ratio C-12/C-13 = 10 in the atmosphere of 39 Cyg are discussed.