THE EVOLUTION OF THE LITHIUM ABUNDANCES OF SOLAR-TYPE STARS .4. PRAESEPE

Echelle observations are presented of lithium in 63 F and G dwarfs of the Praesepe cluster. For stars earlier than about GOV, Praesepe follo ws the same trends seen in the Hyades, which has approximately the sam e age and composition. Stars in Praesepe later than about G5V have mor e Li than their Hyades counterparts, possibly because Praesepe is slig htly younger than the Hyades or has slightly lower metallicity. Signif icant differences in the abundance of Li are seen among stars of the s ame color, and, as in the Hyades, there is a tendency for the deviant stars to be binaries to the extent that duplicity in Praesepe is known . There are also stars with much less Li than most cluster members yet which appear to be true members of Praesepe. The close binary KW 181 has a normal Li abundance, despite the fact that similar close binarie s in the Hyades are Li rich.