1304.3715 (Rachid Ouyed)

A resolution of the cosmic Lithium problem    [PDF]

Rachid Ouyed

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; a discrepancy which is still far from being solved. The most challenging features of the plateau is the lack of variability in the -2.8 < [Fe/H] < -2.0 metallicity range and the "meltdown" (a drop and an increase in variability) for [Fe/H] < -2.8. Here we show how quark-novae (QNe) occurring in the wake of Pop III stars, (a few days to a few weeks following the core-collapse SN explosions of 20-40 M_sun progenitors) 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.

View original: http://arxiv.org/abs/1304.3715