Lithium in optically-selected G and K stars in NGC 6475 (220 Myr)

Abstract

Photometric members of the open cluster NGC 6475 were observed using high resolution spectroscopy for analysis of lithium abundances in their atmospheres. We combine these new data with previously obtained lithium data, and present a comparison with one younger and one older open cluster of similar composition. The most interesting result from these data shows that metallicity is a relatively unimportant feature in describing the evolution of lithium abundance distributions from young (~100 Myr) metal-rich solar-type stars to older ones (~700 Myr). We also argue that there is tentative evidence for different lithium abundance distributions for NGC 6475 members depending on whether they are optically or X-ray selected.