The detailed chemical composition of the atmosphere AY Cet ( HD 7672 ) is determined from a high-resolution spectrum in the optical region .
The main atmospheric parameters and the abundances of 22 chemical elements , including key species such as ^ { 12 } { C } , ^ { 13 } { C } , N , and O , are determined .
A differential line analysis gives T _ { eff } = 5080 K , log g = 3.0 , { [ Fe / H ] } = -0.33 , { [ C / Fe ] } = -0.17 , { [ N / Fe ] } = 0.17 , { [ O / Fe ] } = 0.05 , { C / N } = 1.58 , and \textsuperscript { 12 } C / \textsuperscript { 13 } C = 21 .
Despite the high chromospheric activity , the optical spectrum of AY Cet provides a chemical composition typical for first ascent giants after the first dredge-up .