GALACTIC CHEMICAL EVOLUTION WITH LOW AND HIGH PRIMORDIAL LITHIUM

We discuss two scenarios for the galactic chemical evolution of lithium. In one, the primordial 7Li abundance is taken to be that presently observed in Population II stars. This value is subsequently enriched to the Population I value by stellar sources. In the other scenario, the primordial 7Li abundance is taken to be as high as that suggested by baryon number inhomogeneous cosmological models in which the universe is closed with baryons. This value is then depleted to the present-day Population I value by astration. The Population II value is obtained by gradual main-sequence destruction. Our models include the results of new calculations of lithium destruction and production in stars. The models are constrained by observations of deuterium, lithium, and beryllium as a function of galactic age and by the observed lack of correlation between Fe and Li for metal-poor stars. We find that these constraints can be satisfied by either scenario. We discuss the possibility that the recently derived upper limit to the lithium absorption along the line of sight to SN 1987A may provide a means to distinguish between these two scenarios.