相关论文: Lithium Enrichment Signatures of Planetary Engulfm…
We compare the properties of recent samples of the lithium abundances in halo stars to one another and to the predictions of theoretical models including rotational mixing, and we examine the data for trends with metal abundance. We find…
Surface lithium is depleted when a star goes through the first dredge-up phase, yet $1\%$ of red giants are found to be Li-rich. The formation mechanism for these remains uncertain. We combine observational constraints from GALAH Li-rich…
Lithium is predicted, and observed, to be depleted in contracting, low-mass pre main sequence (PMS) stars. Yet these stars reach the zero age main sequence (ZAMS) with a spread in lithium abundance at a given effective temperature that is…
The application to main-sequence stars of the rotation-induced mixing theory in the presence of mu-gradients leads to partial mixing in the lithium destruction region, not visible in the atmosphere. The induced lithium depletion becomes…
We want to study the effects of the formation of planets and planetary systems on the atmospheric Li abundance of planet host stars. In this work we present new determinations of lithium abundances for 326 Main Sequence stars with and…
Increasing observed data indicate that part of giants has abnormally high lithium (Li) inside their surface, and their proportion is around 1%. Instead of pursuing the feasible mechanisms for extra Li enrichment, we focus on how to inhibit…
Aims. Exoplanet-host stars (EHS) are known to present superficial 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…
We exploit the unique characteristics of a sample of open clusters (OCs) and field stars for which high-precision 7Li abundances and stellar parameters are homogeneously derived by the Gaia-ESO Survey (GES). We derive possibly undepleted…
The behavior of lithium (Li) in Population I main sequence stars challenges standard stellar theory. Two phenomena stand out: the solar Li problem which extends to Li depletion in solar analogs and the Li dip observed in mid-F stars within…
We have refined the estimate of the primordial level of $^7$Li abundance to an accuracy better than 10%, based on high-precision Li abundances for metal-poor halo stars, and a recent model of post-BBN (Big Bang Nucleosynthesis) chemical…
Although not predicted by standard stellar evolution, the surface abundance of light elements, such as lithium (Li), carbon, and nitrogen, changes during the red giant branch (RGB) as a result of extra-mixing. This is associated usually…
We examine the evolution of Li in the Galactic disk,basing our model on the compilation of Li v.Fe observations in stars of iron abundance ranging between halo values,which give a baseline for the disk Li abundance,and 0.2 dex above…
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…
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…
We report the discovery of 23 lithium-rich post-main-sequence stars, identified from moderate-resolution SDSS spectroscopy and confirmed with high-resolution spectra taken at the Hobby-Eberly Telescope. These new Li-rich stars cover a broad…
The surface lithium abundance A(Li) of warm metal-poor dwarf stars exhibits a narrow plateau down to [Fe/H]~-2.8 dex, while at lower metallicities the average value drops by 0.3 dex with a significant star-by-star scatter (called lithium…
We present a study on the detailed elemental abundances of newly identified bright very metal-poor stars with the detection of lithium, initially observed as part of the SDSS/MARVELS pre-survey. These stars were selected for high-resolution…
Metal-poor stars are crucially important for understanding the early Galaxy, first stars, and the Universe. In this series of papers, we present a homogeneous non-local thermodynamic equilibrium (NLTE) abundances analysis of 12 elements for…
The lithium plateau observed in halo stars has long appeared as a paradox in the general context of the lithium abundance behavior in stellar outer layers. First, the plateau is flat, second, the lithium abundance dispersion is extremely…
We study lithium depletion in low-mass and solar-like stars as a function of time, using a new diffusion coefficient describing extra-mixing taking place at the bottom of a convective envelope. This new form is motivated by…