Related papers: The cosmological lithium problem
Accurate spectroscopic lithium abundances are essential in addressing a variety of open questions, such as the origin of a uniform lithium content in the atmospheres of metal-poor stars (Spite plateau) or the existence of a correlation…
Context. The recent detection of nitrogen-enhanced, metal-poor galaxies at high redshift by the James Webb Space Telescope has sparked renewed interest in exploring the chemical evolution of carbon, nitrogen, and oxygen (the CNO elements)…
The discrepancy between the theoretical prediction of primordial lithium abundances and astronomical observations is called the Lithium Problem. We find that extra contributions from non-thermal hydrogen and helium during Big Bang…
The depletion of lithium during the pre-main sequence and main sequence phases of stellar evolution plays a crucial role in the comparison of the predictions of big bang nucleosynthesis with the abundances observed in halo stars. In the…
Recently, we studied the chemical evolution of lithium in the thin disc of the Milky Way. We found that the best agreement with the observed Li abundances in the thin disc is obtained considering novae as the main source of lithium. We…
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…
Context: Lithium is a fragile element, which is easily destroyed in the stellar interior. The existence of lithium-rich giants still represents a challenge for stellar evolution models. Aims: We have collected a large database of…
Using the cosmological constants derived from WMAP, the standard big bang nucleosynthesis (SBBN) predicts the light elements primordial abundances for 4He, 3He, D, 6Li and 7Li. These predictions are in satisfactory agreement with the…
We calculate nucleosynthesis in Population (Pop) III supernovae (SNe) and compare the yields with various abundance patterns of extremely metal-poor (EMP) stars. We assume that the observed EMP stars are the second generation stars, which…
Using high-resolution optical spectroscopy we determine the chemical abundance of the secondary star in the binary millisecond pulsar PSR J1023+0038. We measure a metallicity of [Fe/H] = 0.48 +/- 0.04 which is higher than the Solar value…
Observations of low-metallicity halo stars have revealed a puzzling result: the abundance of \li7 in these stars is at least three times lower than their predicted primordial abundance. It is unclear whether the cause of this disagreement…
The first generation of stars is quite unique. The absence of metals likely affects their formation, with current models suggesting a much more top-heavy initial mass fraction than what we observe today, and some of their other properties,…
Theoretical models of stellar evolution predict that most of the lithium inside a star is destroyed as the star becomes a red giant. However, observations reveal that about 1% of red giants are peculiarly rich in lithium, often exceeding…
We aim to determine the constraints that observed chemical abundances put on the potential role of mass loss in metal poor dwarfs. Self-consistent stellar evolutionary models that include all the effects of atomic diffusion and radiative…
New observations from the Hubble ultra deep field suggest that the star formation rate at z>7 drops off faster than previously thought. Using a newly determined star formation rate for the normal mode of Population II/I stars (PopII/I),…
We present VLT-UVES Li abundances for 28 halo dwarf stars between [Fe/H]=-2.5 and -3.5, 10 of which have [Fe/H]<-3. Four different T_eff scales have been used. Direct Infrared Flux Method (IRFM) has been used on the basis of 2MASS infrared…
A long sought after goal using chemical abundance patterns derived from metal-poor stars is to understand the Galactic chemical evolution (GCE) and to pin down the nature of the first stars (Pop III). Here, we use a sample of 14 metal-poor…
Un-evolved, very metal-poor stars are the most important tracers of the cosmic abundance of lithium in the early universe. Combining the standard Big Bang nucleosynthesis model with Galactic production through cosmic ray spallation, these…
JWST has brought us new insights into Cosmic Dawn with tentative detection of the unique signatures of metal-free Population III (Pop III) stars, such as strong HeII emission, extremely blue UV spectrum, and enhanced nitrogen abundance.…
We have determined Li abundances in 55 metal-poor (3.6 < [Fe/H] < -0.7) stars with extreme orbital kinematics. We find the Li abundance in the Li-plateau stars and examine its decrease in low-temperature, low-mass stars. The Li observations…