相关论文: The evolution of Lithium: implications of a univer…
The standard model of primordial nucleosynthesis by the Big Bang as selected by the WMAP-based estimate of the baryon density ($\Omega_bh^2$) predicts an abundance of $^7$Li that is a factor of three greater than the generally reported…
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 discrepancy has emerged between the cosmic lithium abundance inferred by the WMAP satellite measurement coupled with the prediction of the standard big-bang nucleosynthesis theory, and the constant Li abundance measured in metal-poor halo…
Recent detection of the isotope $^7$Be (that decays into $^7$Li) in the outburst of classical novae confirms the suggestion made in the 70s that novae could make $^7$Li. We reconsidered the role of novae as producers of Li by means of a…
Lithium abundance derived in metal-poor main sequence stars is about three times lower than the value of primordial Li predicted by the standard Big Bang nucleosynthesis when the baryon density is taken from the CMB or the deuterium…
The WMAP determination of the baryon-to-photon ratio implies, through Big Bang nucleosynthesis, a cosmological Li abundance larger, by a factor of 2 to 3, than the Li abundance plateau observed in the oldest Pop II stars. It is however…
We have computed a grid of up-to-date stellar evolutionary models including atomic diffusion, in order to study the evolution with time of the surface Li abundance in low-mass metal-poor stars. We discuss in detail the dependence of the…
The discrepancy between the predictions of primordial nucleosynthesis and the observed lithium abundance in Spite plateau stars has been attributed either to a challenge to the standard model of nucleosynthesis or to stellar processes…
The primordial Lithium Problem is intimately connected to the assumption that ${}^{7}{\rm Li}$ observed in metal-poor halo stars retains its primordial abundance, which lies significantly below the predictions of standard big-bang…
The role of novae as producers of galactic lithium has been suggested since the 1970s, and it has been reconsidered recently with the detection of $^7$Be in their outbursts. At the same time, stellar models are moving forward to comprehend…
A highly homogeneous study of 23 halo field dwarf stars has achieved a Li abundance accuracy of 0.033 dex per star. The work shows that the intrinsic spread of the Li abundances of these stars at a given metallicity is <0.02 dex, and…
The observed lithum (Li) abundance of Galactic halo stars mainly fall within the range of 2.0--2.4 dex. This nearly constant value, known as the Spite plateau, is approximately a factor of three lower than the value predicted from cosmic…
Unraveling the cosmological Li problem - the discrepancy between Big Bang nucleosynthesis predictions and observed values in the Spite plateau - requires a comprehensive exploration of stellar evolution. In this study, we utilized the code…
Lithium abundances have been determined in more than 100 metal-poor halo stars both in the field and in clusters. From these data we find trends of Li with both temperature and metallicity and a real dispersion in Li abundances in the Spite…
We study the temporal evolution of the 7Li abundance in the gaseous medium for all the components (halo, disk and bulge) of our Galaxy. We adopt nucleosynthesis prescriptions on stellar lithium production based upon recent observational…
Since the pioneering observations of Spite & Spite in 1982, the constant lithium abundance of metal-poor ([Fe/H]<-1.3) halo stars near the turnoff has been attributed a cosmological origin. Closer analysis revealed that the observed…
The evolution of the 7Li abundance in the Galaxy has been computed by taking into account several 7Li sources: novae, massive AGB stars, C-stars, Type II SNe and GCRs. The theoretical predictions for the evolution of the 7Li abundance in…
The cosmological lithium problem, i.e. the discrepancy between the lithium abundance predicted by the Big Bang Nucleosynthesis and the one observed for the stars of the "Spite plateau", is one of the long standing problems of modern…
We investigate the distribution of the lithium abundances, A(Li), of metal-poor dwarf and subgiant stars within the limits 5500 K < Teff < 6700 K, -6.0 < [Fe/H] < -1.5, and logg > ~3.5 (a superset of parameters first adopted by Spite and…
The discovery of the Spite plateau in the abundances of 7Li for metal-poor stars led to the determination of an observationally deduced primordial lithium abundance. However, after the success of the Wilkinson Microwave Anisotropy Probe…