Li-rich and super Li-rich giants produced by element diffusion

Context. About 0.2-2% of giant stars are Li-rich, whose lithium abundance (A(Li)) is higher than 1.5 dex. Among them, near 6% super Li-rich with A(Li) exceeding 3.2 Meanwhile, the formation mechanism these and giants still under debate. Aims. Considering compact He core red giants, attention paid to effect element diffusion on A(Li). In particular, when flash occurs, makes thermohaline mixing zone extend inward connect inner convection region stars. Then, a large amount 7Be produced by can be transferred stellar surface, finally turning into 7Li. Thus, goal this work propose enrichment achieve consistency between theoretical observation data. Methods. Using Modules for Experiments in Stellar Astrophysics (MESA), we simulate evolution low-mass stars, considering effects Li abundances. The timescale ratio normal estimated population synthesis method. Then get value make comparison observations. Results. influence model results increase up about 1.8dex, which reveal giants. Simultaneously, introducing high constant diffusive coefficients (Dmix) values from 10e11 10e15in allows 2.4 4.5dex, explain most method reveals that among 0.2-2%, consistent levels.