1999ApJ...511..218J -
Astrophys. J., 511, 218-224 (1999/January-3)
Lithium in Blanco 1: implications for stellar mixing.
JEFFRIES R.D. and JAMES D.J.
Abstract (from CDS):
We obtain lithium abundances for G and K stars in Blanco 1, an open cluster with an age similar to or slightly younger than the Pleiades. We critically examine previous spectroscopic abundance analyses of Blanco 1 and conclude that, while there were flaws in earlier work, it is likely that Blanco 1 is close in overall metallicity to the older Hyades cluster and more metal-rich than the Pleiades. However, we find Blanco 1 has Li abundances and rotation rates similar to the Pleiades, contradicting predictions from standard stellar evolution models, in which convective pre-main-sequence (PMS) Li depletion should increase rapidly with metallicity. If the high metallicity of Blanco 1 is subsequently confirmed, our observations imply (1) that a currently unknown mechanism severely inhibits PMS Li depletion; (2) that additional nonstandard mixing modes, such as those driven by rotation and angular momentum loss, are then responsible for main-sequence Li depletion between the ages of Blanco 1 and the Hyades; and (3) that in clusters younger than the Hyades, metallicity plays only a minor role in determining the amount of Li depletion among G and K stars. These conclusions suggest that Li abundance remains a useful age indicator among young (<700 Myr) stars even when metallicities are unknown. If nonstandard mixing is effective in Population I stars, the primordial Li abundance could be significantly larger than present day Population II Li abundances because of prior Li depletion.
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Journal keyword(s):
Galaxy: Open Clusters and Associations: Individual: Name: Blanco 1 - Stars: Abundances - stars: interiors - stars: late-type
Simbad objects:
38
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