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Related papers: Lithium-rich M-dwarfs at the ZAMS: Evidence for pl…

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We have carried out a high resolution spectroscopic survey of the 220-250 Myr old cluster NGC 6475: our main purpose is to investigate Li evolution during the early stages of the Main Sequence. We have determined Li abundances for 33 late F…

Astrophysics · Physics 2009-11-07 Paola Sestito , Sofia Randich , Jean-Claude Mermilliod , Roberto Pallavicini

Li abundances are derived for a sample of bulgelike stars with isochronal ages of 10-11 Gyr. These stars have orbits with pericentric distances, Rp, as small as 2-3 kpc and Zmax < 1 kpc. The sample comprises G and K dwarf stars in the…

Astrophysics · Physics 2009-11-07 Luciana Pompeia , Beatriz Barbuy , Michel Grenon , Bruno Castilho

Context: Knowledge of the age distribution of stars in young clusters and associations is crucial to constrain models of star formation. HR diagrams of different young clusters and associations suggest the presence of age spreads, but the…

Astrophysics · Physics 2009-11-11 G. G. Sacco , S. Randich , E. Franciosini , R. Pallavicini , F. Palla

We present the results of a photometric and spectroscopic survey of cool M dwarf candidates in the young open cluster NGC 2547. Using the 2dF fiber spectrograph, we have searched for the luminosity at which lithium remains unburned in an…

Intermediate resolution spectroscopy from the ESO Very Large Telescope is analysed for 63 photometrically selected low-mass (0.08-0.30 Msun) candidates of the open cluster NGC 2547. We have confirmed membership for most of these stars using…

Astrophysics · Physics 2009-11-10 R. D. Jeffries , J. M. Oliveira

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…

Solar and Stellar Astrophysics · Physics 2025-04-28 R. J. Jackson , R. D. Jeffries , E. Tognelli

We present results from a spectroscopic study of the very low mass members of the Southern open cluster Blanco 1 using the Gemini-N telescope. We obtained intermediate resolution (R~4400) GMOS spectra for 15 cluster candidate members with…

Solar and Stellar Astrophysics · Physics 2015-05-20 P. A. Cargile , D. J. James , R. D. Jeffries

We present an extensive study of lithium abundances in dwarf components of chromospherically active binary stars (CABS). Since most of these binaries have known radii, masses and ages, this kind of data is especially useful for comparisons…

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…

Astrophysics · Physics 2008-11-26 Sofia Randich , Paola Sestito , Roberto Pallavicini

It has recently been suggested that all giant stars with mass below 2 $M_{\odot}$ suffer an episode of surface lithium enrichment between the tip of the red giant branch (RGB) and the red clump (RC). We test if the above result can be…

Planetary engulfment events have long been proposed as a lithium (Li) enrichment mechanism contributing to the population of Li-rich giants (A(Li) >= 1.5 dex). Using MESA stellar models and A(Li) abundance measurements obtained by the GALAH…

Solar and Stellar Astrophysics · Physics 2021-12-08 M. Soares-Furtado , Matteo Cantiello , Morgan MacLeod , Melissa K. Ness

This study investigates the temporal and spatial variations in lithium abundance within the Milky Way using a sample of 22,034 main-sequence turn-off (MSTO) stars and subgiants, characterised by precise stellar ages, 3D NLTE (non-local…

Astrophysics of Galaxies · Physics 2024-11-21 Tiancheng Sun , Shaolan Bi , Xunzhou Chen , Yuxi , Lu , Yuqin Chen , Ming-Yi Ding , Jianrong Shi , Hongliang Yan , Zhishuai Ge

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…

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…

We consider WIYN/Hydra spectra of 329 photometric candidate members of the 420-Myr-old open cluster M48, and report Lithium detections or upper limits for 234 members and likely members. The 171 single members define a number of notable…

Solar and Stellar Astrophysics · Physics 2023-07-26 Qinghui Sun , Constantine P. Deliyannis , Aaron Steinhauer , Barbara J. Anthony-Twarog , Bruce A. Twarog

Late M-type dwarfs in the solar neighborhood include a mixture of very low-mass stars and brown dwarfs which is difficult to disentangle due to the lack of constraints on their age such as trigonometric parallax, lithium detection and space…

Solar and Stellar Astrophysics · Physics 2017-03-22 N. Phan-Bao , M. S. Bessell , D. Nguyen-Thanh , E. L. Martín , P. T. P. Ho , C. F. Lee , H. Parsons

The Gaia-ESO survey recently reported on a large sample of lithium (Li) abundance determinations for evolved stars in the rich open cluster Trumpler 20. They argue for a scenario where virtually all stars experience post main sequence…

Solar and Stellar Astrophysics · Physics 2016-12-21 Claudia Aguilera-Gómez , Julio Chanamé , Marc H. Pinsonneault , Joleen K. Carlberg

During Big Bang nucleosynthesis (BBN) in the first 15 minutes of the Universe some $^7$Li was created along with isotopes of H and He. The determination of that primordial value of Li can help constrain the conditions at that time. The…

Solar and Stellar Astrophysics · Physics 2024-06-26 Ann Merchant Boesgaard , Constantine P. Deliyannis

We show that non-magnetic models for the evolution of pre-main-sequence (PMS) stars *cannot* simultaneously describe the colour-magnitude diagram (CMD) and the pattern of lithium depletion seen in the cluster of young, low-mass stars…

We present lithium abundances for 119 main-sequence stars in the old open cluster NGC 188 (age = 6.3 Gyr), using high-resolution, high signal-to-noise ratio spectra from WIYN/Hydra. We observe the stars over multiple nights and measure…

Solar and Stellar Astrophysics · Physics 2025-09-19 Qinghui Sun , Constantine P. Deliyannis , Bruce A. Twarog , Barbara J. Anthony-Twarog
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