The chemical composition of the red giant η Ser

The paper presents the results of an analysis of elemental abundances in the atmosphere of η Ser—a red giant of spectral type K2IIIabCN1, according to Hoffleit and Jaschek 4]. The resulting atmospheric parameters correspond to a K0 giant, and the peculiarities of the star’s chemical composition provide evidence that the assignment of η Ser to the class of CN stars was erroneous.