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We have obtained new photometry and intermediate resolution ($\Delta \lambda = 2.7$ \AA\ ) spectra of 19 of these objects (14.9 $\le$ $I_c$ $\le$ 17.5) in order to confirm cluster membership. We identify 15 of our targets as likely cluster…

Astrophysics · Physics 2011-02-11 D. Barrado y Navascues , J. R. Stauffer , B. M. Patten

Despite the extensive study of lithium depletion during pre-main-sequence contraction, studies of individual stars show discrepancies between ages determined from the HR diagram and ages determined from lithium depletion (Song et al. 2002,…

Solar and Stellar Astrophysics · Physics 2015-05-18 Jennifer C. Yee , Eric L. N. Jensen

Determination of the lithium depletion boundary (LDB), i.e., the observational limit below which the cores of very low-mass objects do not reach high enough temperature for Li destruction, has been used to obtain ages for several open…

Solar and Stellar Astrophysics · Physics 2018-04-04 Eduardo L. Martín , Nicolas Lodieu , Yakiv Pavlenko , Víctor J. S. Béjar

We have identified a large number of possible very low mass members of the cluster IC2391 based primarily on their location in an I versus (R-I)_C CM diagram. We have obtained new photometry and low resolution ($\Delta \lambda = 2.7$ \AA)…

Astrophysics · Physics 2007-05-23 D. Barrado y Navascues , J. R. Stauffer , B. M. Patten

Optical spectroscopy is used to confirm membership for 8 low-mass candidates in the young Beta Pic moving group (BPMG) via their radial velocities, chromospheric activity and kinematic parallaxes. We searched for the presence of the Li I…

Solar and Stellar Astrophysics · Physics 2015-06-17 A. S Binks , R. D. Jeffries

Astrometry and photometry from {\it Gaia} and spectroscopic data from the {\it Gaia}-ESO Survey (GES) are used to identify the lithium depletion boundary (LDB) in the young cluster NGC 2232. A specialised spectral line analysis procedure…

We have derived accurate and homogeneous Lithium abundances in 49 main sequence binary systems belonging to the Hyades Open Cluster by using a deconvolution method to determine individual magnitudes and colors for the primary and secondary…

Astrophysics · Physics 2007-05-23 D. Barrado y Navascues , J. R. Stauffer

We present an analysis of the lithium abundances in late spectral type binaries of different ages. They belong to several open clusters (Pleiades, Hyades and M67), as well as to Chromospherically Active Binary Systems (CABS). All these…

Astrophysics · Physics 2007-05-23 David Barrado y Navascues

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…

We take a critical look at the lithium depletion boundary (LDB) technique that has recently been used to derive the ages of open clusters. We identify the sources of experimental and systematic error and show that the probable errors are…

Astrophysics · Physics 2007-05-23 R. D. Jeffries , T. Naylor

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

Lithium (Li) is a powerful tracer of stellar mixing, gradually depleted in solar twins by non-standard transport below the convective zone. Here, we identify six new solar twins with exceptionally low Li levels that are not explained by…

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

The dispersed remnants of stellar nurseries, stellar associations provide unparalleled samples of coeval stars critical for studies of stellar and planetary formation and evolution. The Carina Stellar Association is one of the closest…

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…

Solar and Stellar Astrophysics · Physics 2026-03-20 Cheng-Cheng Xie , Hai-Jun Tian , Jian-Rong Shi , Ze-Ming Zhou

We present a deep Cousins RI photometric survey of the open cluster NGC 1960, complete to R_C \simeq 22, I_C \simeq 21, that is used to select a sample of very low-mass cluster candidates. Gemini spectroscopy of a subset of these is used to…

Solar and Stellar Astrophysics · Physics 2015-06-16 R. D. Jeffries , Tim Naylor , N. J. Mayne , Cameron P. M. Bell , S. P. Littlefair

Stellar ages are key to improving our understanding of different astrophysical phenomena. However, many techniques to estimate stellar ages are highly model-dependent. The lithium depletion boundary (LDB), based on the presence or absence…

High-dispersion spectra centered on the Li 6708 A line have been obtained for 70 potential members of the open cluster NGC 3680, with an emphasis on stars in the turnoff region. A measurable Li abundance has been derived for 53 stars, 39 of…

Solar and Stellar Astrophysics · Physics 2015-05-13 B. J. Anthony-Twarog , C. P. Deliyannis , B. A. Twarog , K. V. Croxall , J. D. Cummings

We want to determine the lithium abundances of solar twin stars as a function of stellar age to provide constraints for stellar evolutions models and to investigate whether there is a connection between low Li abundance and the occurrence…

Solar and Stellar Astrophysics · Physics 2016-02-24 Marilia Carlos , Poul E. Nissen , Jorge Melendez

We examine the internal structure of solar-like stars in detail between 0.8 and 1.4M Sun and during pre-main sequence phase. Recent opacity computations of OPAL along with a new hydrodynamical mixing process have been considered. We also…

Astrophysics · Physics 2008-11-26 L. Piau , S. Turck-Chieze
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