Related papers: Pre-main-sequence Lithium Depletion
The surface content of lithium (Li) and beryllium (Be) provide insights into the mixing and circulation mechanisms in stellar interiors. The old open cluster, M 67, has been well-studied for Li abundances in both main-sequence and evolved…
A growing disquiet has emerged in recent years that standard stellar models are at odds with observations of the colour-magnitude diagrams (CMDs) and lithium depletion patterns of pre main sequence (PMS) stars in clusters. In this work we…
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…
The existence of one percent of lithium-rich giant stars among normal, lithium-poor giant stars continues to be poorly explained. By merging two catalogues, one containing 10,535 lithium-rich giant stars with lithium abundances ranging 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 aim to constrain the mixing processes in low-mass stars by investigating the behaviour of the Li surface abundance after the main sequence. We take advantage of the data from the sixth internal data release of Gaia-ESO, idr6, and from…
While theoretical computations of the lithium abundances in Pop II stars predict variations from star to star, the most recent observations confirm the existence of a "lithium plateau" with no abundance dispersion. This apparent paradox has…
We discuss the effects of convective overshooting in the PMS evolution of intermediate mass stars, by analysing in detail the early evolution towards the main sequence of a 2 M_sun stellar model. These effects can be extremely important in…
I shall review what has been learnt during 20 years of lithium observations in stars belonging to metal-poor globular clusters. The focus will be on little evolved main-sequence, turnoff-point (TOP) and subgiant-branch (SGB) stars expected…
The formation and evolution of light elements in the Universe act as important cosmological constraints. It has long been assumed that the oldest stars of the Galaxy display the primordial Li abundance in their outer layers, although…
We have determined Li abundances for 11 G-type stars in the 6-8 Gyr old open cluster NGC 188. These data significantly enlarge the number of cluster stars with Li measurements, allowing us to extend the investigation of Li depletion in open…
We studied the formation and evolution of low-mass stars within halos with high concentration of dark matter (DM) particles, using a highly sophisticated expression to calculate the rate at which DM particles are captured inside the star.…
We present NLTE Li abundances for 88 stars in the metallicity range -3.5 < [Fe/H] < -1.0. The effective temperatures are based on the infrared flux method with improved E(B-V) values obtained mostly from interstellar NaI D lines. The Li…
We compute rotating 1D stellar evolution models that include a modified temperature gradient in convection zones and criterion for convective instability inspired by rotating 3D hydrodynamical simulations performed with the MUSIC code. In…
We investigated the possibility of producing helium enhanced stars in globular clusters by accreting polluted matter during the pre-main sequence phase. We followed the evolution of two different classes of pre-main sequence accreting…
Stars do not simply pop up on the main sequence. Before the stars arrive on the zero-age main sequence, they form in the collapses of molecular clouds, gain matter through accretion processes, and compress their cores until hydrogen can…
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 develop new angular momentum evolution models for stars with masses of $0.5$ to $1.6~\rm M_\odot$ and from the pre-main-sequence (\rm PMS) through the end of their main-sequence (\rm MS) lifetime. The parametric models include magnetic…
We present evolutionary models for low mass stars and brown dwarfs ($m \le 1.2 \msol$) based on recent improvement of the theory: equation of state, atmosphere models, ... We concentrate on early evolutionary phases from the initial…
We identify 6 early M-dwarfs, in 3 open clusters (NGC 2451a, Blanco 1 and NGC 2516) at ages of 50-200 Myr, that are anomalously enriched in lithium compared with Li-depleted siblings of similar spectral type. The Li-rich outliers represent…