A resolution of the cosmic Lithium problem

Abstract

In 1982, Monique and Francois Spite discovered that the 7Li abundance in the atmosphere of old metal-poor dwarf stars in the galactic halo was independent of metallicity and temperature. Since then, 7Li abundance in the Universe has become a subject of intrigue, because there is less of it in Population II dwarf stars (by a factor of 3) than standard big bang nucleosynthesis predicts. Here we show how quark-novae (QNe) occurring in the wake of Pop. III stars, can elegantly produce an A(Li) ~ 2.2 Lithium plateau in Pop. II (low-mass) stars formed in the pristine cloud swept up by the mixed SN+QN ejecta. We also find an increase in the scatter as well as an eventual drop in A(Li) below the Spite plateau values for very low metallicity ([Fe/H] < -3) in excellent agreement with observations. We propose a solution to the discrepancy between the Big Bang Nucleosynthesis 7Li abundance and the Spite plateau and list some implications and predictions of our model.