LITHIUM DILUTION THROUGH MAIN-SEQUENCE MASS-LOSS

We investigate the consequences of main-sequence mass loss for surface lithium abundances in stars through the use of evolving, mass-losing stellar models. In particular, we attempt to model lithium depletion observed in three areas: the Sun, the Hyades G dwarfs, and the Hyades F dwarfs. Mass loss as an explanation for lithium depletion has mixed success. We conclude that mass loss can be a marginal explanation for the solar lithium problem. In the case of the Hyades G dwarfs (the 'classical Hyades lithium problem") we find, contrary to preliminary investigations by ourselves and others, that mass loss cannot be a significant contributor to the depletion seen in these stars. Furthermore, we show that quasi-analytical means alone are sufficiently accurate to model the quantitative consequences of mass loss in these stars. For the Hyades F dwarfs, mass loss is a viable, although not particularly aesthetic, explanation. We highlight features that a theory of mass loss must possess to explain the remarkable pattern of lithium depletion seen among F dwarfs in the Hyades, in other clusters, and in the field. With the results of our calculations we limit the amount of mass that may have been lost on the main sequence by Hyades F and G dwarfs.