Lithium in Stars on the Main Sequence and Beyond

Abstract

7Li provides a rare constraint on the baryonic density of the Universe and because of its fragile nature, it is also an excellent diagnostic of the physical processes occurring inside stars. The study of Li in Pop.I stars is crucial to understanding its primordial abundance. Observations suggest that a vast majority of them deplete their Li severely, in contrast to the predictions of the standard stellar models. A fresh study of 130 stars we undertook supports the idea that the large spread in Li is driven by the rotational history of the star. Open clusters reveal much more because each represents a sample with the same age and metallicity. I discuss briefly what we have learnt from their studies.