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相关论文: Oxygen from the Lambda 7774 High-Excitation Triple…

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We present the results of our abundance analysis of Fe, Ni, and O in high S/N, high-resolution VLT/UVES and McDonald/2dcoude spectra of nine dwarfs and three giants in the Hyades open cluster. The difference in Fe abundances derived from Fe…

天体物理学 · 物理学 2009-09-29 S. C. Schuler , A. P. Hatzes , J. R. King , M. Kuerster , L. -S. The

We present oxygen abundances of dwarfs in the young open cluster IC 4665 deduced from the OI $\lambda$7774 triplet lines and of dwarfs in the open cluster Pleiades derived from the [OI] $\lambda$6300 forbidden line. Stellar parameters and…

天体物理学 · 物理学 2011-02-11 Z. -X. Shen , X. -W. Liu , H. -W. Zhang , B. Jones , D. N. C. Lin

It has been occasionally suggested that Fe abundances of K dwarfs derived from Fe I and Fe II lines show considerable discrepancies and oxygen abundances determined from high-excitation O I 7771-5 triplet lines are appreciably overestimated…

太阳与恒星天体物理 · 物理学 2020-04-08 Yoichi Takeda , Satoshi Honda

In an attempt to carry out a systematic study on the behavior of the photospheric abundances of Li, C, and O (along with Fe) for Hyades main-sequence stars in the T_eff range of ~5000-7000K, we conducted an extensive spectrum-synthesis…

太阳与恒星天体物理 · 物理学 2015-06-12 Yoichi Takeda , Satoshi Honda , Takashi Ohnishi , Michiko Ohkubo , Ryuko Hirata , Kozo Sadakane

We discuss oxygen abundances derived from [O I] 6300 and the O I triplet in stars spanning a wide range in chromospheric activity level, and show that these two indicators yield increasingly discrepant results with higher…

天体物理学 · 物理学 2009-11-10 T. Morel , G. Micela

Oxygen abundances of 34 B-type stars in the effective temperature range of Teff~10000-28000K with diversified rotational velocities (vesini~ 0-250km/s) were determined from the OI triplet lines at 7771-5A, with an aim to examine whether…

太阳与恒星天体物理 · 物理学 2016-04-06 Yoichi Takeda , Satoshi Honda

Using classical model atmospheres and an LTE analysis, Mg isotope ratios 24Mg:25Mg:26Mg are measured in 32 Hyades dwarfs covering 4000K < Teff < 5000K. We find no significant trend in any isotope ratio versus Teff and the mean isotope ratio…

天体物理学 · 物理学 2009-11-10 David Yong , David L. Lambert , Carlos Allende Prieto , Diane B. Paulson

We report a comprehensive light element (Li, C, N, O, Na, Mg, and Al) abundance analysis of three solar-type main sequence (MS) dwarfs and three red giant branch (RGB) clump stars in the Hyades open cluster using high-resolution and high…

太阳与恒星天体物理 · 物理学 2009-08-05 S. C. Schuler , J. R. King , L. -S. The

We have derived Fe abundances of 16 solar-type Pleiades dwarfs by means of an equivalent width analysis of Fe I and Fe II lines in high-resolution spectra obtained with the Hobby - Eberly Telescope and High Resolution Spectrograph.…

太阳与恒星天体物理 · 物理学 2015-05-19 S. C. Schuler , A. L. Plunkett , J. R. King , M. H. Pinsonneault

We employ a new Infrared Flux Method (IRFM) temperature scale (Ramirez & Melendez 2005, ApJ 626, 446; ApJ 626, 465) in order to determine Li, O, and Fe NLTE abundances in a sample of relatively unevolved (dwarfs, turn-off, subgiants)…

天体物理学 · 物理学 2009-11-11 Jorge Melendez , Nataliya G. Shchukina , Ivan Ramirez , Irina Vasiljeva

Abundances of 15 chemical elements have been derived for 28 F and 16 A stars members of the Hyades open cluster in order to set constraints on self-consistent evolutionary models including radiative and turbulent diffusion. A spectral…

太阳与恒星天体物理 · 物理学 2015-05-19 M. Gebran , M. Vick , R. Monier , Luca Fossati

We present a detailed study of the non-Local Thermodynamic Equilibrium (non-LTE) formation of the high-excitation neutral oxygen 777 nm triplet in MARCS model atmospheres representative of late-type stars with spectral types F to K. We…

太阳与恒星天体物理 · 物理学 2015-05-13 D. Fabbian , M. Asplund , P. S. Barklem , M. Carlsson , D. Kiselman

Using standard 1D-LTE model atmosphere analysis, we provide an in-depth investigation of iron abundance as derived from neutral and singly ionization iron lines (Fe {\scriptsize{I, II}}) in nearby star clusters. Specifically, we replicate…

太阳与恒星天体物理 · 物理学 2017-09-06 Patrick D. Aleo , Alexander C. Sobotka , Ivan Ramirez

One of the most important factors in determining the stellar lithium abundance is the effective temperature. In a previous study by the authors, new effective temperatures Teff for sixteen metal-poor halo dwarfs were derived using a local…

太阳与恒星天体物理 · 物理学 2015-05-18 A. Hosford , A. E. Garcia Perez , R. Collet , S. G. Ryan , J. E. Norris , K. A. Olive

We present a detailed and uniform study of oxygen abundances in 155 solar type stars, 96 of which are planet hosts and 59 of which form part of a volume-limited comparison sample with no known planets. EW measurements were carried out for…

天体物理学 · 物理学 2009-11-11 A. Ecuvillon , G. Israelian , N. C. Santos , N. G. Shchukina , M. Mayor , R. Rebolo

We use new and extant literature spectroscopy to address abundances and membership for UMa moving group stars. We first compare the UMa, Coma, and Hyades H-R diagrams via a homogeneous set of isochrones, and find that these three aggregates…

天体物理学 · 物理学 2009-11-11 Jeremy R. King , Simon C. Schuler

Hydra spectra of 85 G-K dwarfs in the young cluster, M35, near the Li 6708 Angstrom line region are analyzed. From velocities and Gaia astrometry, 78 are likely single-star members which, combined with previous work, produces 108 members…

太阳与恒星天体物理 · 物理学 2018-07-18 B. J. Anthony-Twarog , C. P. Deliyannis , D. Harmer , D. B. Lee-Brown , A. Steinhauer , Q. Sun , B. A. Twarog

Lithium abundances in a sample of halo dwarfs have been redetermined by using the new T$_{eff}$ derived by Fuhrmann et al (1994) from modelling of the Balmer lines. These T$_{eff}$ are reddening independent, homogeneous and of higher…

天体物理学 · 物理学 2007-05-23 P. Molaro , F. Primas , P. Bonifacio

The discovery of the Spite plateau in the abundances of 7Li for metal-poor stars led to the determination of an observationally deduced primordial lithium abundance. However, after the success of the Wilkinson Microwave Anisotropy Probe…

天体物理学 · 物理学 2009-11-13 A. Hosford , S. G. Ryan , A. E. Garcia Perez , J. E. Norris , K. A. Olive

We use high quality VLT/UVES published data of the permitted OI triplet and FeII lines to determine oxygen and iron abundances in unevolved (dwarfs, turn-off, subgiants) metal-poor halo stars. The calculations have been performed both in…

天体物理学 · 物理学 2010-11-11 J. Melendez , N. G. Shchukina , I. E. Vasiljeva , I. Ramirez
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