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The current status of observational studies of lithium depletion in open clusters is reviewed, concentrating mainly on G and K type stars. I attempt to answer the following questions: Can the lithium depletion patterns seen in open clusters…

Astrophysics · Physics 2007-05-23 R. D. Jeffries

Context: A small number of K-type giants on the red giant branch (RGB) is known to be very rich in lithium (Li). This fact is not accounted for by standard stellar evolution theory. The exact phase and mechanism of Li enrichment is still a…

Solar and Stellar Astrophysics · Physics 2015-06-03 Thomas Lebzelter , Stefan Uttenthaler , Maurizio Busso , Mathias Schultheis , Bernhard Aringer

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…

The primordial Lithium Problem is intimately connected to the assumption that ${}^{7}{\rm Li}$ observed in metal-poor halo stars retains its primordial abundance, which lies significantly below the predictions of standard big-bang…

Astrophysics of Galaxies · Physics 2022-04-08 Brian D. Fields , Keith A. Olive

The aim of this work is to search for Li-rich giants in a sample of clusters where planets have been searched, thus we can study the planet engulfment scenario to explain Li replenishment using a proper comparison sample of stars without…

Solar and Stellar Astrophysics · Physics 2016-02-17 E. Delgado Mena , M. Tsantaki , S. G. Sousa , M. Kunitomo , V. Adibekyan , P. Zaworska , N. C. Santos , G. Israelian , C. Lovis

Lithium is one of the few elements produced during the Big Bang Nucleosynthesis in the early universe. Moreover, its fragility makes it useful as a proxy for stellar environmental conditions. As such, the lithium abundance in old systems is…

A Li-rich red giant star (2M19411367+4003382) recently discovered in the direction of NGC 6819 belongs to the rare subset of Li-rich stars that have not yet evolved to the luminosity bump, an evolutionary stage where models predict Li can…

The cosmological {7Li problem consists in explaining why the primordial Li abundance, as predicted by the standard Big Bang nucleosynthesis theory with constraints from WMAP and Planck, is a factor of 3 larger than the Li abundance measured…

Astrophysics of Galaxies · Physics 2021-05-12 Francesca Matteucci , Marta Molero , David S. Aguado , Donatella Romano

We present an analysis of Li abundances in low mass stars (LMS) during the Red Giant Branch (RGB) and Asymptotic Giant Branch (AGB) stages, based on a new determination of their luminosities and evolutionary status. By applying recently…

Solar and Stellar Astrophysics · Physics 2015-05-13 R. Guandalini , S. Palmerini , M. Busso , S. Uttenthaler

The lithium abundances of planet-harbouring stars have been compared with those of open clusters and field stars. Young (chromospherically active) and subgiant stars have been eliminated from the comparison because they are at different…

Astrophysics · Physics 2009-10-31 Sean G. Ryan

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…

Astrophysics · Physics 2007-05-23 J. D. do Nascimento , C. Charbonnel , A. Lebre , P. de Laverny , J. R. De Medeiros

Reconstructing the Galactic evolution of lithium (Li) is the main tool used to constrain the source(s) of Li enrichment in the Galaxy. Recent results have suggested a decline in Li at supersolar metallicities, which may indicate reduced…

First-ascent red giants with strong and very strong Li lines have just been discovered in globular clusters. Using the stellar internal prompt 7Li enrichment - mass loss scenario, we explore the possibility of 7Li enrichment in the…

Astrophysics · Physics 2009-10-31 Ramiro de la Reza , Licio da Silva , Natalia A. Drake , Marco A. Terra

We present a new Doppler imaging study for the Li-rich single K-giant DI Psc. Surface temperature maps are reconstructed for two subsequent rotation cycles. From the time evolution of the spot distribution antisolar-type differential…

Solar and Stellar Astrophysics · Physics 2015-06-17 Levente Kriskovics , Zsolt Kővári , Krisztián Vida , Katalin Oláh

The orbital angular momentum of a close-orbiting giant planet can be sufficiently large that, if transferred to the envelope of the host star during the red giant branch (RGB) evolution, it can spin-up the star's rotation to unusually large…

Solar and Stellar Astrophysics · Physics 2012-09-13 Joleen K. Carlberg , Katia Cunha , Verne V. Smith , Steven R. Majewski

Lithium is a fragile but crucial chemical element in the universe, exhibits interesting and complex behaviors. Thanks to the massive spectroscopic data from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST)…

This paper extends our previous study of planet/brown dwarf accretion by giant stars to solar mass stars located on the red giant branch. The model assumes that the planet is dissipated at the bottom of the convective envelope of the giant…

Astrophysics · Physics 2015-06-24 Lionel Siess , Mario Livio

We reanalyze the problem of Li abundances in red giants of nearly solar metallicity. After an outline of the problems affecting our knowledge of the Li content in low-mass stars (M<3Mo), we discuss deep-mixing models for the RGB stages…

Solar and Stellar Astrophysics · Physics 2015-05-28 S. Palmerini , S. Cristallo , M. Busso , C. Abia , S. Uttenthaler , L. Gialanella , E. Maiorca

Parameters and abundances for 1133 stars of spectral types F, G, and K of luminosity class III have been derived. In terms of stellar parameters, the primary point of interest is the disagreement between gravities derived with masses…

Solar and Stellar Astrophysics · Physics 2015-09-16 R. Earle Luck

We present Lithium abundance determination for a sample of K giant stars in the galactic bulge. The stars presented here are the only 13 stars with detectable Lithium line (6767.18 A) among ~400 stars for which we have spectra in this…

Solar and Stellar Astrophysics · Physics 2015-05-13 O. A. Gonzalez , M. Zoccali , L. Monaco , V. Hill , S. Cassisi , D. Minniti , A. Renzini , B. Barbuy , S. Ortolani , A. Gomez