The chemical composition of stars in the globular clusters M 10, M 12, and M 71

The abundances of 19 chemical elements in the atmospheres of five stars belonging to three globular clusters have been determined by applying the model-atmosphere method to 430.0-790.0 nm spectra obtained with the echelle spectrometer of the 6-m telescope of the Special Astrophysical Observatory. The abundances of silicon, calcium, iron-peak elements, copper, zinc, and neutron-capture elements follow the abundance patterns for halo stars. The abundance of sodium in M 10 giants provides evidence that different mixing mechanisms operate in halo and Cluster stars or that light elements are enriched in different ways in the pre-stellar matter from which some globular Clusters and halo stars were formed. (C) 2003 MAIK Nauka/Interperiodica.