Detailed analysis of nearby bulgelike dwarf stars.: II.: Lithium abundances

Li abundances are derived for a sample of bulgelike stars with isochronal ages of 10-11 Gyr. These stars have orbits with pericentric distances, R-p, as small as 2-3 kpc and Z(max) < 1 kpc. The sample comprises G and K dwarf stars in the metallicity range -0.80 <= [Fe/H] <= +0.40. Few data on Li abundances in old turnoff stars (>= 4.5 Gyr) within the present metallicity range are available. M67 (4.7 Gyr) and NGC 188 (6 Gyr) are the oldest studied metal-rich open clusters with late-type stars. Li abundances have also been studied for a few samples of old metal-rich field stars. In the present work, a high dispersion in Li abundances is found for bulgelike stars with all metallicity ranges, comparable with values in M67. The role of metallicity and age on a Li depletion pattern is discussed. The possible connection between Li depletion and oxygen abundance due to atmospheric opacity effects is investigated.