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A.I. Sills (Ohio State U.), C.P. Deliyannis (Indiana U.)
We present models of subgiant stars in M67 which follow the surface abundances of lithium and beryllium. These models include a number of physical processes which have been proposed as explanations for the main sequence depletion of lithium in the Hyades. We use the observed lithium abundance as a function of temperature in the M67 subgiants, and the correlation between lithium and beryllium depletion to distinguish between these models. We find that mass loss and diffusion are strongly ruled out as viable mechanisms for light element depletion in main sequence stars. Rotationally induced mixing can be consistent with the observed abundances of lithium in the subgiants in M67. Such rotational mixing models are strongly supported by the correlation of lithium and beryllium abundances observed in Population I field F stars.
The author(s) of this abstract have provided an email address for comments about the abstract: asills@astronomy.ohio-state.edu