THE ASTRONOMICAL JOURNAL      VOLUME 106, NUMBER 3, PAGE 1080    SEPTEMBER 1993

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

                   DAVID R. SODERBLOM AND STEPHEN B. FEDELE

     Space Telescope Science Institute, 3700 San Martin Drive, Baltimore,
                                Maryland 21218
                     Electronic mail: soderblom@stsci.edu

                                BURTON F. JONES

Lick Observatory, Board of Studies of Astronomy and Astrophysics, University of
                   California, Santa Cruz, California 95064
                    Electronic mail: jones@helios.ucsc.edu

                    JOHN R. STAUFFER AND CHARLES F. PROSSER

   Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge,
                              Massachusetts 02138
      Electronic mail: stauffer@cfa.harvard.edu, prosser@cfa.harvard.edu


                                   ABSTRACT

    Echelle observations are presented of lithium in 63 F and G dwarfs of
    the Praesepe cluster.  For stars earlier than about G0V, Praesepe
    follows the same trends seen in the Hyades, which has approximately the
    same age and composition.  Stars in Praesepe later than about G5V have
    more Li than their Hyades counterparts, possibly because Praesepe is
    slightly younger than the Hyades or has slightly lower metallicity.
    Significant differences in the abundance of Li are seen among stars of
    the same 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 binaries in the Hyades are Li rich.