Y, Ba, and La abundance in the stars of open clusters and Galactic field

The lanthanum abundances were determined by the synthetic spectrum method using the VLT spectra of 30 stars of eight open clusters, namely Ruprecht 4, Ruprecht 7, Berkeley 25, Berkeley 73, Berkeley 75 and NGC 6192, NGC 6404, NGC 6583. The analyses of the behaviour of the yttrium, barium, and lanthanum abundances with ages in the stars of the open clusters and galactic field were carried out. We found that the scatter of the barium abundances is larger than those of the yttrium and lanthanum. The resulting scatter can be caused by both real causes and methods of abundance determinations (using the equivalent widths of the lines, LTE approach, etc.). The traced trends of Y, Ba, La abundances with the age can indicate the growth of contribution in the n-capture enrichments from low-mass AGB stars. Comparison of the barium and lanthanum abundances with ages for a thin disc stars (\citealt{mis13a}) and those obtained by us for the open cluster stars, shows that the lanthanum as well as barium demonstrates large values for several clusters, but its value is only reaches 0.3 dex. The barium overabundance in the cluster Ruprecht 7 may be indicative of other ways (not AGB stars) barium enrichment.