Quantitative Analysis of the Spectrum of HD 108564

Abstract

A quantitative analysis of the spectrum of HD 108564 is performed. It is a star of the main sequence of spectral class K5V, the atmosphere of which is depleted in metals. The high-quality observed HARPS spectra are downloaded from the ESO archive. Abundances of elements in the atmosphere are obtained by fit of observational profiles of the C I lines and selected lines of the C₂ molecules, and the O I, Ca I, Si I, Sc II, Cr I, CI, OI, Na I, Mg I, Si I, Ca I, Sc II, Ti I, Ti II, Cr I, Mn I, Fe I, Fe II, Co I, Ni I, Cu I, and Zn I. Abundances are determined iteratively, with a recalculation of the input parameters, which are effective temperature T_eff  at a fixed value of gravity logg (or log g for a fixed T_eff value). The effect of variations of T_eff  or log g, which provide the same abundances of A(Fe I) and A(Fe II), on the abundances of other elements are determined. The obtained results indicate an excess of light elements (C, O, and Si) compared to the group of iron. The absence of the lithium line at 670.8 nm is confirmed with an estimate of A(Li) < –12.5 for the upper limit of lithium abundance in the abundance scale, in which the sum of all abundances is 1.0. The determined radial velocity equal to V_rad = 111.21 km/s is consistent with the known estimates of other researchers. Apparent rotation velocity V sin i = 1.12 ± 0.5 km/s is determined.