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相关论文: The lithium-rotation correlation for WTTS in Tauru…

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We compare the properties of recent samples of the lithium abundances in halo stars to one another and to the predictions of theoretical models including rotational mixing, and we examine the data for trends with metal abundance. We find…

天体物理学 · 物理学 2008-11-26 M. H. Pinsonneault , G. Steigman , T. P. Walker , V. K. Narayanan

We have determined Li abundances in 55 metal-poor (3.6 < [Fe/H] < -0.7) stars with extreme orbital kinematics. We find the Li abundance in the Li-plateau stars and examine its decrease in low-temperature, low-mass stars. The Li observations…

天体物理学 · 物理学 2009-11-13 Ann Merchant Boesgaard , Alex Stephens , Constantine P. Deliyannis

We present an analysis of K2 light curves (LCs) from Campaigns 4 and 13 for members of the young ($\sim$3 Myr) Taurus association, in addition to an older ($\sim$30 Myr) population of stars that is largely in the foreground of the Taurus…

太阳与恒星天体物理 · 物理学 2020-06-03 L. M. Rebull , J. R. Stauffer , A. M. Cody , L. A. Hillenbrand , J. Bouvier , N. Roggero , T. J. David

We investigate a sample of 6 Herbig Ae/Be stars belonging to the Orion OB1 association, as well as 73 low mass objects, members of the $\sigma$ Orionis cluster, in order to explore the angular momentum evolution at early stages of…

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

We report the discovery of a peculiar set of old super-metal-rich dwarf stars with orbits of low eccentricity that reach a maximum height from the Galactic plane between $\sim$ 0.5-1.5 kpc observed by the \emph{Gaia}-ESO Survey. These stars…

太阳与恒星天体物理 · 物理学 2025-01-29 M. L. L. Dantas , R. Smiljanic , R. Boesso , H. Rocha-Pinto , L. Magrini , G. Guiglion , D. Romano

The evolution of rotating stars with zero-age main sequence (ZAMS) masses in the range 8 to 25 M_sun is followed through all stages of stable evolution. The initial angular momentum is chosen such that the star's equatorial rotational…

天体物理学 · 物理学 2008-11-26 A. Heger , N. Langer , S. E. Woosley

Metal-poor stars are crucially important for understanding the early Galaxy, first stars, and the Universe. In this series of papers, we present a homogeneous non-local thermodynamic equilibrium (NLTE) abundances analysis of 12 elements for…

With the calculated guiding center radius $R_{guiding}$ and birth radius $R_{birth}$, we investigate the role of radial migration on the description of lithium evolution in the Galactic disk based on the upper envelope of the A(Li) vs.…

星系天体物理 · 物理学 2023-02-13 Haopeng Zhang , Yuqin Chen , Gang Zhao , Shaolan Bi , Xianfei Zhang , Xiangxiang Xue

We present a study of the evolutionary state of a few lithium-rich giant stars based on the Gaia DR2 parallaxes and photometry. We also investigate the chromospheric activity, the presence of a surface magnetic field, and the radial…

太阳与恒星天体物理 · 物理学 2020-09-09 B. F. O. Gonçalves , J. S. da Costa , L. de Almeida , M. Castro , J. -D. do Nascimento

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…

天体物理学 · 物理学 2009-11-10 David L. Lambert , Bacham E. Reddy

The surface lithium abundance A(Li) of warm metal-poor dwarf stars exhibits a narrow plateau down to [Fe/H]~-2.8 dex, while at lower metallicities the average value drops by 0.3 dex with a significant star-by-star scatter (called lithium…

太阳与恒星天体物理 · 物理学 2022-06-01 A. Mucciarelli , L. Monaco , P. Bonifacio , M. Salaris , M. Deal , M. Spite , O. Richard , R. Lallement

As a test of rotationally-induced mixing causing the well-known Li dip in older mid-F dwarfs in the local Galactic disk, we utilize high-resolution and -S/N Keck/HIRESspectroscopy to measure the Li abundance in the components of the1 Gyr,…

太阳与恒星天体物理 · 物理学 2015-06-16 Patrick Baugh , Jeremy R. King , Constantine P. Deliyannis , Ann Merchant Boesgaard

We present stellar rotation rates derived from Transiting Exoplanet Survey Satellite (TESS) light curves for stars in Upper Centaurus-Lupus (UCL; ~136 pc, ~16 Myr) and Lower Centaurus-Crux (LCC; ~115 pc, ~17 Myr). We find spot-modulated…

太阳与恒星天体物理 · 物理学 2022-08-17 L. M. Rebull , J. R. Stauffer , L. A. Hillenbrand , A. M. Cody , Ethan Kruse , Brian P. Powell

We report mid--IR observations of two young stars found in the Taurus dark cloud spatially resolving for the first time their 10 $\mu$m emission. The weak-emission T Tauri star DI Tau, tentatively identified by Skrutskie et al. (1990) on…

天体物理学 · 物理学 2009-10-30 Michael R. Meyer , S. V. W. Beckwith , T. M. Herbst , M. Robberto

The current status of observational studies of lithium depletion in open clusters is reviewed, concentrating mainly on G and K type stars. I attempt to answer the following questions: Can the lithium depletion patterns seen in open clusters…

天体物理学 · 物理学 2007-05-23 R. D. Jeffries

Observations have shown that the effective temperature of hydrogen-free Wolf-Rayet (WR) stars is considerably lower than that of the standard model, which means that the radius of the observed H-free WR stars is several times larger than…

太阳与恒星天体物理 · 物理学 2023-06-28 Xizhen Lu , Chunhua Zhu , Helei Liu , Sufen Guo , Jinlong Yu , Guoliang Lü

Stellar evolution calculations were carried out from the main sequence to the final AGB stage of stars with initial masses from 1 to $2M_\odot$ and metallicity $Z=0.01$. Selected models of evolutionary sequences were used as initial…

太阳与恒星天体物理 · 物理学 2018-09-11 Yuri Fadeyev

Reconstructing the Galactic evolution of lithium (Li) is the main tool used to constrain the source(s) of Li enrichment in the Galaxy. Recent results have suggested a decline in Li at supersolar metallicities, which may indicate reduced…

The "stellar" solution to the cosmological lithium problem proposes that surface depletion of lithium in low-mass, metal-poor stars can reconcile the lower abundances found for Galactic halo stars with the primordial prediction. Globular…

太阳与恒星天体物理 · 物理学 2015-05-18 K. Lind , F. Primas , C. Charbonnel , F. Grundahl , M. Asplund