O Prof. Dr. Jorge Melendez (IAG/USP) apresenta Seminário do Departamento de Astronomia.
Resumo/Abstract:
The standard model of big bang nucleosynthesis for the WMAP-based baryon density, predicts a primordial lithium abundance about 2-6 times higher than the Li abundance inferred from metal-poor stars in the Spite plateau. This cosmological discrepancy could be explained either by new exciting physics or by stellar depletion. We will present new precise Li abundances based on spectra of metal-poor stars obtained with the UVES spectrograph at VLT/ESO. Adding the new stars to our previous high precision sample, we cover a broad range of effective temperatures in the metallicity range -3.5 < [Fe/H] < -1.0. Our data suggest that Li has been depleted in halo stars, alleviating thus the discrepancy between stellar Li abundances and the primordial Li abundance predicted from BBN+WMAP.