Related papers: Lithium and Beryllium in One Solar Mass Stars
Spectroscopically determined Li abundances of metal-poor turn-off dwarfs are known to be nearly constant (Spite plateau), but lower than the primordial value expected from the standard cosmological model. However, abundance determination by…
Study of primary stars lying in Sirius-like systems with various masses of WD companions and orbital separations is one of the key aspects to understand the origin and nature of Barium (Ba) stars. In this paper, based on high resolution and…
Lithium (Li) abundance is an age indicator for G, K, and M stellar types, as its abundance decreases over time for these spectral types. However, despite the observational efforts made over the past few decades, the role of rotation,…
The observations of light elements in the Sun and Solar type stars give special clues for understanding the hydrodynamical processes at work in stellar interiors. In the Sun 7Li is depleted by 140 while 3He has not increased by more than…
Lithium abundances and rotation, determined for 120 subgiant stars in Lebre et al. (1999) are analyzed. To this purpose, the evolutionary status of the sample as well as the individual masses have been determined using the HIPPARCOS…
The process of convective settling is based on the assumption that a small fraction of the low-entropy downflows sink from the photosphere down to the bottom of the star's envelope convection zone retaining a substantial entropy contrast.…
Compilations of abundances of Strontium and Barium in extremely metal-poor stars show that an apparent cutoff is observed for [Sr/Ba] at [Fe/H]$<$-3.6 and large fluctuations for [Fe/H]$>$-3.6 with a clear upper bound depending on…
This contribution presents an overview of the evolution of Li abundances in stars of the Galactic thin and thick discs, from the observational point of view. The focus is on Li abundances obtained by recent projects and surveys. To separate…
Barium stars are unusually enriched in barium ([Ba/Fe] >= 1.0 dex) and not predicted by current Galactic chemical evolution models. Previous observations of barium stars have found evidence that they form through mass transfer from a…
The structural stratification of a solar-type main sequence star primarily depends on its mass and chemical composition. The surface heavy element abundances of the solar-type stars are reasonably well determined using conventional…
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…
We present FLAMES/GIRAFFE spectroscopy obtained at the Very Large Telescope (VLT). Using these observations we have been able for the first time to observe the Li I doublet in the Main Sequence stars of a Globular Cluster. We also observed…
We review the main sources of LiBeB production and show that a primary mechanism is at work in the early Galaxy involving both ejection and acceleration of He, C and O at moderate energy, which by nuclear interaction with H and He produce…
Be stars are widely considered to be the product of binary interaction. However, whether all Be stars are formed via binary interaction is unclear, and detailed estimates of the multiplicity of Be stars and characterization of their…
Star clusters have long been used to illuminate both stellar evolution and Galactic evolution. They also hold clues to the chemical and nucleosynthetic processes throughout the history of the Galaxy. We have taken high signal-to-noise,…
Observations and modelling of stars with near-solar masses in their early phases of evolution is critical for a better understanding of how dynamos of solar-type stars evolve. We examine the chemical composition and the spot distribution of…
Investigating the apparent anomalies in lithium (Li) surface abundance observed in the Sun and young stellar globular clusters holds significant promise for advancing our understanding of the mechanisms influencing Li depletion. This study…
We have investigated a group of stars known to have low chromospheric ages, but high kinematical ages. Isochrone, chemical and lithium ages are estimated for them. The majority of stars in this group show lithium abundances much smaller…
[ABRIDGED] We determine Li abundances for a well-studied sample of 714 F and G dwarf, turn-off, and subgiant stars in the solar neighbourhood. The analysis is based on line synthesis of the Li line at 6707 {\AA} in high-resolution and high…
We present chemical composition and fundamental parameters (the effective temperature, surface gravity and radius) for four sharp-lined A-type stars ${\gamma}$ Gem (HD 41705), o Peg (HD 214994), ${\theta}$ Vir (HD 114330) and ${\nu}$ Cap…