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Origin of Li in K giants : some clues from spectroscopic survey

Eswar Reddy (Indian Institute of Astrophysics - Bangalore)

A handful of giants in the Galaxy show Li which is by a factor of 100-1000 compared to what is expected from the standard models and observed in vast majority of K giants. Recently, we have taken up a systematic low resolution spectroscopic survey to understand the problem.
I discuss our findings from the survey. Survey resulted fifteen new Li-rich giants including four super Li-rich K giants (log ε(Li)≥3.2) which increased the current known Li-rich K giants by a factor of 2-3. A significant finding is that there is a concentration of Li-rich K giants in the narrow luminosity range. The finite luminosity spread of the Li-rich giants serves to reject the idea that Li enhancement is, in general, a consequence of a giant swallowing a large planet. A few possible scenarios for the Li production are discussed.