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相关论文: A Lithium Age for the Young Cluster IC2391

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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…

太阳与恒星天体物理 · 物理学 2015-05-13 B. J. Anthony-Twarog , C. P. Deliyannis , B. A. Twarog , K. V. Croxall , J. D. Cummings

We present an updated catalog of 1300 objects in the field of M31, including 670 likely star clusters of various types. Archival images were inspected to confirm cluster classifications where possible, but most of the classifications were…

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,…

太阳与恒星天体物理 · 物理学 2015-05-18 Jennifer C. Yee , Eric L. N. Jensen

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…

We report on the properties of 89 low mass star clusters located in the vicinity of luminous young clusters (blue globulars) in the disk of M31. 82 of the clusters are newly detected. We have determined their integrated magnitudes and…

星系天体物理 · 物理学 2015-05-13 P. W. Hodge , O. K. Krienke , M. Bellazzini , S. Perina , P. Barmby , J. G. Cohen , T. H. Puzia , J. Strader

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…

太阳与恒星天体物理 · 物理学 2024-06-26 Ann Merchant Boesgaard , Constantine P. Deliyannis

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…

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…

太阳与恒星天体物理 · 物理学 2015-06-17 A. S Binks , R. D. Jeffries

We report the evidence that several low-mass stars (<~0.4 Msun) of the Orion and Upper Scorpius clusters have lithium abundances well below the interstellar value. Due to time-dependent depletion, our result implies stellar ages greater…

天体物理学 · 物理学 2015-11-11 Francesco Palla , Sofia Randich

[Abridged] Contex. Young open clusters provide important clues to the interface between the main sequence and pre-main-sequence phases of stellar evolution. The young and nearby open cluster IC 2391 is well-suited to studies of these two…

We present spectroscopic optical and photometric infrared observations of 12 faint candidate members of the young open cluster Alpha Persei found by Prosser (1994). Keck HIRES echelle spectra provide radial and rotational velocity…

天体物理学 · 物理学 2009-10-30 Gibor Basri , Eduardo L. Martin

We present a new, BVIc photometric survey of the young open cluster IC4665, which improves on previous studies of this young cluster by incorporating a rigorous standardization procedure, thus providing high-fidelity colors and magnitudes…

太阳与恒星天体物理 · 物理学 2015-05-19 Phillip A. Cargile , David J. James

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.…

太阳与恒星天体物理 · 物理学 2015-05-14 L. da Silva , C. A. O. Torres , R. de la Reza , G. R. Quast , C. H. F. Melo , M. Sterzik

The Lithium Depletion Boundary (LDB) is a robust method for accurately determining the ages of young clusters, but most pre-main-sequence models used to derive LDB ages do not include the effects of magnetic activity on stellar properties.…

太阳与恒星天体物理 · 物理学 2015-06-22 Aaron J. Juarez , Phillip A. Cargile , David J. James , Keivan G. Stassun

Previous studies of open clusters have shown that lithium depletion is not only strongly age dependent but also shows a complex pattern with other parameters that is not yet understood. For pre- and main-sequence late-type stars, these…

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…

天体物理学 · 物理学 2009-11-07 R. D Jeffries , J. M. Oliveira , D. Barrado y Navascues , J. R. Stauffer

We have carried out a survey of compact star clusters (apparent size <3 arcsec) in the southwest part of the M31 galaxy, based on the high-resolution Suprime-Cam images (17.5 arcmin x 28.5 arcmin), covering ~15% of the deprojected galaxy…

星系天体物理 · 物理学 2009-11-18 V. Vansevicius , K. Kodaira , D. Narbutis , R. Stonkute , A. Bridzius , V. Deveikis , D. Semionov

Old open clusters are very useful targets to investigate mechanisms responsible for lithium (Li) depletion during the main sequence. Comparison of the Li abundances in clusters of different age allows us to understand the efficiency of the…

天体物理学 · 物理学 2009-11-13 Loredana Prisinzano , Sofia Randich

We present a statistical and multiwavelength photometric studies of young open cluster IC 1590. We identified 91 cluster members using $Gaia$ DR3 astrometry data using ensemble-based unsupervised machine learning techniques. From $Gaia$…

星系天体物理 · 物理学 2024-02-26 A. H. Sheikh , Biman J. Medhi

We present spectroscopic ages, metallicities, and [alpha/Fe] ratios for 70 globular clusters in M31 that were derived from Lick line-index measurements. In addition to a population of old (>10 Gyr) globular clusters with a wide range of…

天体物理学 · 物理学 2009-11-10 Thomas H. Puzia , Kathy M. Perrett , Terry J. Bridges