Dipartimento di Scienze Fisiche ed Astronomiche,
Università di Palermo
Osservatorio Astronomico di Palermo "Giuseppe S. Vaiana"

Palermo - 18 Gennaio 2002

AVVISO DI SEMINARIO

Il Dott. Piercarlo Bonifacio
dell'Osservatorio Astronomico di Trieste terrà il seminario:

``Observations of Li in metal-poor stars, new results on field and globular cluster stars"

il 25 Gennaio 2002 alle ore 11:00 , presso l'aula del Osservatorio Astronomico di Palermo.

SOMMARIO

I review our present understanding of Li in metal-poor stars both in the field and in globular clusters. I use new data, both spectroscopic and photometric to argue that the Li observed in metal-poor stars is of primordial origin which enables us to use Li as a baryometer. The derived baryonic density is in agreement, within errors, with recent measures derived from estimates of the primordial abundance of D, 3He and from the fluctuations of the cosmic microwave background. The standard big bang model is strongly supported by all these observations; a slight tension might still exist for 4He, on whose primordial abundance a debate is still open.