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We report the discovery of eight lithium-rich field giants found in a high resolution spectroscopic sample of over 700 metal-poor stars ([Fe/H]<-0.5) selected from the RAVE survey. The majority of the Li-rich giants in our sample are very…

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,…

Solar and Stellar Astrophysics · Physics 2024-05-15 D. Cuenda-Muñoz , D. Barrado , M. A. Agüeros , J. L. Curtis , H. Bouy

Thanks to the high multiplex and efficiency of Giraffe at the VLT we have been able for the first time to observe the Li I doublet in the Main Sequence (MS) stars of a Globular Cluster. At the same time we observed Li in a sample of…

Astrophysics of Galaxies · Physics 2015-05-14 J. I. González Hernández , P. Bonifacio , E. Caffau , M. Steffen , H. -G. Ludwig , N. Behara , L. Sbordone , R. Cayrel , S. Zaggia

The prediction of the PLANCK-constrained primordial lithium abundance in the Universe is in discordance with the observed Li abundances in warm Population II dwarf and subgiant stars. Among the physically best motivated ideas, it has been…

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…

Astrophysics · Physics 2011-05-05 M. H. Pinsonneault , T. P. Walker , G. Steigman , V. K. Narayanan

The emergence of the disc in our Galaxy and the relation of the thick and thin disc formation and evolution is still a matter of debate. The chemo-dynamical characterization of disc stars is key to resolve this question, in particular at…

We derive atmospheric parameters and lithium abundances for 671 stars and include our measurements in a literature compilation of 1381 dwarf and subgiant stars. First, a "lithium desert" in the effective temperature (Teff) versus lithium…

Solar and Stellar Astrophysics · Physics 2015-06-05 I. Ramirez , J. R. Fish , D. L. Lambert , C. Allende Prieto

Preliminary abundances of lithium and a few other elements have been obtained for 31 field Am stars with good Hipparcos parallaxes, as well as for 36 normal A and F stars. Radial and projected rotational velocities were determined as well.…

Astrophysics · Physics 2009-11-11 P. North , F. Betrix , C. Besson

Lithium abundances are presented for a sample of 181 nearby F and G dwarfs with accurate {\it Hipparcos} parallaxes. The stars are on circular orbits about the Galactic centre and, hence, are identified as belonging to the thin disk. This…

Astrophysics · Physics 2009-11-10 David L. Lambert , Bacham E. Reddy

In this work we present the results of our analysis of 16,300 medium-resolution LAMOST spectra of late-type stars in the Kepler field with the aim of determining the stellar parameters, activity level, lithium atmospheric content, and…

Solar and Stellar Astrophysics · Physics 2022-08-17 A. Frasca , J. Molenda-Zakowicz , J. Alonso-Santiago , G. Catanzaro , P. De Cat , J. N. Fu , W. Zong , J. X. Wang , T. Cang , J. T. Wang

Our study is a follow-up of the SACY project, an extended survey in the Southern Hemisphere targeted to search for young nearby associations. Nine associations have either been newly identified, or had their member list better defined.…

Solar and Stellar Astrophysics · Physics 2015-05-14 L. da Silva , C. A. O. Torres , R. de la Reza , G. R. Quast , C. H. F. Melo , M. Sterzik

In the two previous papers of this series, we have discussed the importance of t he $\mu$-gradients due to helium settling on rotation-induced mixing, first in a n approximate analytical way, second in a 2D numerical simulation. We have…

Astrophysics · Physics 2009-11-07 Sylvie Theado , Sylvie Vauclair

Since 1995, more than 1500 exoplanets have been discovered around a large diversity of host stars (from M- to A-type stars). Tidal dissipation in stellar convective envelopes is a key actor that shapes the orbital architecture of…

Solar and Stellar Astrophysics · Physics 2015-07-29 S. Mathis

Lithium abundances are presented and discussed for 70 members of the 50 Myr old open cluster alpha Per. More than half of the abundances are from new high-resolution spectra. The Li abundance in the F-type stars is equal to its presumed…

Solar and Stellar Astrophysics · Physics 2015-05-19 Suchitra C. Balachandran , Sushma V. Mallik , David L. Lambert

Lithium's susceptibility to burning in stellar interiors makes it an invaluable tracer for delineating the evolutionary pathways of stars, offering insights into the processes governing their development. Observationally, the complex Li…

Transport processes occurring in the radiative interior of solar-type stars are evidenced by the surface variation of light elements, in particular Li, and the evolution of their rotation rates. For the Sun, inversions of helioseismic data…

Solar and Stellar Astrophysics · Physics 2021-02-10 T. Dumont , A. Palacios , C. Charbonnel , O. Richard , L. Amard , K. Augustson , S. Mathis

We have measured v sin i with high precision for a sample of dM3 stars (86 targets). We detected rotation in 82 stars (73 dM3 stars, and 9 dM3e stars). We compare our measurements of v sin i for all the stars in our dM0, dM2, dM3 and dM4…

Solar and Stellar Astrophysics · Physics 2015-06-23 E. R. Houdebine , D. J. Mullan

Two series of models and their yields are presented in this paper. The first series consists of 20 Mo models with varying initial metallicity (solar down to $Z=10^{-8}$) and rotation (Vini=0-600 km/s). The second one consists of models with…

Astrophysics · Physics 2009-11-11 Raphael Hirschi

High resolution (R=110000), very high S/N spectra, centered on the 6707.8A LiI line have been obtained with the ESO Coude Echelle Spectrometer for five, metal-poor (-0.8 < [Fe/H] < -0.6) disk stars in the turnoff region of the HR-diagram.…

Astrophysics · Physics 2007-05-23 P. E. Nissen , D. L. Lambert , F. Primas , V. V. Smith

Lithium abundances, radial velocities and rotational velocities are reported for 20 candidate F, G and K stars of the sparse Coma Berenices open cluster. All the stars are proper-motion selected, and our radial velocities support the…

Astrophysics · Physics 2009-11-06 A. Ford , R. D. Jeffries , D. J. James , J. R. Barnes