相关论文: The Lithium Plateau Enigma

Lithium is extensively known to be a good tracer of non-standard mixing processes occurring in stellar interiors. We present the results of a new large Lithium survey in red giant stars and combine it with surveys from the literature to…

I summarize the stellar side of the cosmological lithium problem(s). Evidence from independent studies is accumulating and indicates that stars may very well be fully responsible for lowering their surface lithium from the predicted…

The success of primordial nucleosynthesis has been limited by the long-standing Lithium problem. We use a self-consistent perturbative analysis of the effects of relevant theoretical parameters on primordial nucleosynthesis, including…

We have performed a differential, line-by-line, chemical abundance analysis, ultimately relative to the Sun, of nine very metal-poor main sequence halo stars, near [Fe/H]=$-$2 dex. Our abundances range from…

Using a sample of 116 wide binary systems as coeval and chemically homogeneous stellar pairs, we investigate the factors governing lithium depletion in main-sequence stars. We recover the well-established morphology of the…

We discuss the current status of the sample of Lithium abundances in extremely metal poor (EMP) turn-off (TO) stars collected by our group, and compare it with the available literature results. In the last years, evidences have accumulated…

Exoplanet-host stars (EHS) are known to present surface chemical abundances different from those of stars without any detected planet (NEHS). EHS are, on the average, overmetallic compared to the Sun. The observations also show that, for…

We present a scenario to explain the lithium-rich phase which occurs on the red giant branch at the so-called bump in the luminosity function. The high transport coefficients required to enhance the surface lithium abundance are obtained in…

About 1% of giant stars have been shown to have large surface Li abundances, which is unexpected according to standard stellar evolution models. Several scenarios for lithium production have been proposed, but it is still unclear why these…

The disagreement between theoretical predictions and observations for surface lithium abundance in stars is a long-standing problem, which indicates that the adopted physical treatment is still lacking in some points. However, thanks to the…

We have determined Li abundances for eleven metal-poor turn-off stars, among which eight have [Fe/H]<-3, based on LTE analyses of high-resolution spectra obtained with the HDS on the Subaru telescope. The Li abundances for four of these…

In the context of the standard model of particle physics, there is a definite upper limit to the density of stable compact stars. However, if there is a deeper layer of constituents, below that of quarks and leptons, stability may be…

One of the most important factors in determining the stellar lithium abundance is the effective temperature. In a previous study by the authors, new effective temperatures Teff for sixteen metal-poor halo dwarfs were derived using a local…

The cosmological constant problem represents an evident tension between our present description of gravity and particle physics. Many solutions have been proposed, but experimental tests are always difficult or impossible to perform and…

The lithium problem arises from the significant discrepancy between the primordial 7Li abundance as predicted by BBN theory and the WMAP baryon density, and the pre-Galactic lithium abundance inferred from observations of metal-poor…

Lithium is an excellent tracer of mixing in stars as it is destroyed (by nuclear reactions) at a temperature around $\sim 2.5\times 10^6$ K. The lithium destruction zone is typically located in the radiative region of a star. If the…

The light element lithium is formed by nucleosynthesis during the Big Bang. Its abundance can help to define the parameters of the early universe. To find this primordial value, it is necessary to determine Li abundances in the oldest stars…

In an attempt to carry out a systematic study on the behavior of the photospheric abundances of Li, C, and O (along with Fe) for Hyades main-sequence stars in the T_eff range of ~5000-7000K, we conducted an extensive spectrum-synthesis…

The discordance between `low' and `high' primordial D/H measurements can be considerably reduced if the analysis of the H+D profiles accounts for the correlated velocity field of bulk motion. We have re-estimated the value of D/H at z=3.572…

Precise abundance ratios are determined for 94 dwarf stars with 5200 < Teff < 6300 K, -1.6 < [Fe/H] < -0.4, and distances D < 335 pc. Most of them have halo kinematics, but 16 thick-disk stars are included. Equivalent widths of atomic lines…