Lithium Abundances in Giants as a Function of Stellar Mass: Evidence for He Flash as the Source of Li Enhancement in Low-mass Giants

Abstract In this work, we studied the distribution of lithium abundances in giants as a function stellar mass. We used sample 1240 common among Kepler photometric and LAMOST medium-resolution ( R ? 7500) spectroscopic survey fields. The asteroseismic ? P –? ? diagram is to define core He-burning red clump giant branch stars with an inert He core. Li have been derived using spectral synthesis for all stars. Directly measured values parameters (or ?? 1 ) are either taken from literature or study. Of 777 identified giants, found 668 low-mass (?2 M ? primary 109 high-mass (>2 secondary giants. Observed agree theoretical model predictions. lack Li-rich presence Li-rich, including super reinforces idea that helium flash holds key enrichment results will further constrain models searching physical mechanism enhancement Results also serve observational evidence only mass less than ?2 develop degenerate undergo flash.