[Previous] | [Session 41] | [Next]
C. P. Deliyannis (Indiana University), D. Barrado y Navascues (Universidad Autonoma de Madrid, Spain), J. R. Stauffer (Caltech (IPAC))
M35 is a very rich open cluster whose age, while somewhat uncertain, is certainly older than the Pleiades and may be up to about 100 Myr older. M35 is slightly metal-poor ( [Fe/H] = -0.21 +/- 0.10 ) as compared to the Pleiades' solar metallicity. We have previously presented WIYN/Hydra observations of the Li region in 39 G and K dwarf radial-velocity-probable-members of M35. In comparison to the Pleiades, the M35 dwarfs show, a) a much smaller range of rotation rates, and much smaller maximum vsini, b) slightly lower Li abundances, c) a much smaller spread in the Li abundances, and d) for those few stars with strikingly different vsini at a given mass, a correlation between Li and rotation (just like in the Pleiades). Possible reasons for these phenomena include: a) M35's older age has enabled stars to spin down more and destroy more Li, b) M35's lower metallicity might imply a different distribution of initial angular momenta (Jo) and spin-down; this distribution might be both tighter and lower in central value, resulting in the tighter Li distribution (however, the older cluster M34 shows a larger range of Li abundances as compared to M35), c) the distribution in Jo simply varies from cluster to cluster, and d) the apparent large spread Li spread in the Pleiades is spurious, and is possibly related to effects of rapid rotation (e.g. on spots, activity); hence, the smaller rotation rates in M35 preclude detection of a spurious Li spread in this cluster. With the hopes of providing new insights in addressing these conflicting explanations, we present a new sample of high signal-to-noise, high resolution (about 20,000) WIYN/Hydra Li observations of 35 G and K dwarfs in M35. This doubles the previous sample, and extends it to later types (late K). This work is supported by NSF Grant AST-9812735 (CPD), Spanish ``Plan Nacional del Espacio" Grant ESP98-1339-CO2 (DB), and NASA Grants NAGW-2698 and 3690 (JRS).