In this Letter, we report on a low-resolution spectroscopic survey for Li-rich K giants among 2000 low mass (M ≤ 3M ⊙ ) giants spanning the luminosity range from below to above the luminosity of the clump. Fifteen new Li-rich giants including four super Li-rich K giants (log ǫ(Li) ≥ 3.2) were discovered. A significant finding is that there is a concentration of Li-rich K giants at the luminosity of the clump or red horizontal branch. This new finding is partly a consequence of the fact that our low-resolution survey is the first large survey to include giants well below and above the RGB bump and clump locations in the HR diagram. Origin of the lithium enrichment may be plausibly attributed to the conversion of 3 He via 7 Be to 7 Li by the Cameron-Fowler mechanism but the location for onset of the conversion is uncertain. Two possible opportunities to effect this conversion are discussed: the bump in the first ascent of the red giant branch (RGB) and the He-core flash at the tip of the RGB. 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.

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In this letter, we report the discovery of 24 new super Li-rich (A(Li) ≥ 3.2) giants of He-core burning phase at red clump region. Results are based on systematic search of a large sample of about 12,500 giants common to the LAMOST spectroscopic and Kepler time resolved photometric surveys. The two key parameters derived from Kepler data; average period spacing (∆p) between l = 1 mixed gravity dominated g-modes and average large frequency separation (∆ν) l = 0 acoustic p-modes, suggest all the Li-rich giants are in He-core burning phase. This is the first unbiased survey subjected to a robust technique of asteroseismic analysis to unambiguously determine evolutionary phase of Li-rich giants. The results provide a strong evidence that Li enhancement phenomenon is associated with giants of Hecore burning phase, post He-flash, rather than any other phase on RGB with inert He-core surrounded by H-burning shell.