The Creation of Superrich Lithium Giants

A time-dependent «convective diffusion» algorithm has been coupled for the first time with a self-consistent full evolutionary computation in order to investigate theoretically the creation of superrich lithium stars on the asymptotic giant branch. Stars of 3, 4, 5, 6, and 7 M ⊙ stars are considered, for Z = 0.02 and Z = 0.001. Superrich lithium stars were produced when convective envelope base temperatures exceeded 50 × 10 6 K. Abundances of log e( 7 Li) ∼4.5 were obtained for stars of mass 4-6 M ⊙ , lying in the luminosity range M bol ∼ -6 to -7, in excellent agreement with observations