The lithium abundance of Hyades main-sequence stars

From high-quality Reticon spectra of Hyades G and K dwarfs, their lithium abundance is found to decline much more rapidly with decreasing temperature than heretofore realized. Previous observations of the 6707 Li I doublet for the cooler dwarfs have probably been contaminated by blends. However, the new lithium-temperature relation still does not agree with simple models of lithium burning in the convective zone, either with or without overshooting. Models have therefore to include other mechanisms for lithium depletion.