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Related papers: The Lithium Depletion Boundary in NGC 2547 as a te…

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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 present the results of a spectroscopic survey of X-ray selected, low-mass candidate members of the young open cluster NGC 2547. Using a combination of photometry, spectroscopic indices and radial velocities we refine our candidate list…

Astrophysics · Physics 2009-11-07 R. D Jeffries , J. M. Oliveira , D. Barrado y Navascues , J. R. Stauffer

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 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

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

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 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

We have used fibre spectroscopy to establish cluster membership and examine pre-main-sequence (PMS) lithium depletion for low-mass stars (spectral types F to M) in the sparse young (~30 Myr) cluster IC 4665. We present a filtered candidate…

Solar and Stellar Astrophysics · Physics 2015-05-13 R. D. Jeffries , R. J. Jackson , D. J. James , P. A. Cargile

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

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

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

We estimate cluster ages from lithium depletion in five pre-main-sequence groups found within 100 pc of the Sun: TW Hydrae Association, Eta Chamaeleontis Cluster, Beta Pictoris Moving Group, Tucanae-Horologium Association and AB Doradus…

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 a study of mass segregation of the young (20-35 Myr isochronal age), open cluster NGC 2547. We find good evidence that mass segregation exists in NGC 2547 down to 3 Msun, and weak evidence for mass segregation down to 1 Msun.…

Astrophysics · Physics 2009-11-10 S. P. Littlefair , Tim Naylor , R. D. Jeffries , C. R. Devey , S. Vine

We present an empirical model of age-dependent photospheric lithium depletion, calibrated using a large, homogeneously-analysed sample of 6200 stars in 52 open clusters, with ages from 2--6000 Myr and $-0.3<{\rm [Fe/H}]<0.2$, observed in…

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…

Pre-main sequence models with inflated radii are needed to simultaneously reproduce the colour-magnitude diagram and the lithium depletion pattern in young open clusters. We tested a new set of PMS models including radius inflation due to…

IC 4665 is one of only a dozen young open clusters with a ``lithium depletion boundary" (LDB) age. Using an astrometrically and spectroscopically filtered sample of cluster members, we show that both the positions of its low mass stars in…

Solar and Stellar Astrophysics · Physics 2023-09-15 R. D. Jeffries , R. J. Jackson , A. S. Binks

Star clusters are ideal platforms for categorising X-ray emitting stars and to study X-ray emission as a function of stellar age and activity. We present a comprehensive study of an open star cluster, NGC2527, by combining data from…

Solar and Stellar Astrophysics · Physics 2020-03-11 Nevil Shah , K. P. Singh , Annapurni Subramaniam
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