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We have derived Mn abundances for more than 200 stars in 19 globular clusters. In addition, Mn abundance determinations have been made for a comparable number of halo field and disk stars possessing an overlapping range of metallicities and…

天体物理学 · 物理学 2008-11-26 J. S. Sobeck , I. I. Ivans , J. A. Simmerer , C. Sneden , P. Hoeflich , J. P. Fulbright , R. P. Kraft

High-resolution spectra of 13 core helium-burning stars in the thick disk of the Galaxy have been obtained with the SOFIN spectrograph on the Nordic Optical Telescope to investigate abundances of up to 22 chemical elements. Abundances of…

天体物理学 · 物理学 2009-11-07 G. Tautvaisiene , B. Edvardsson , I. Tuominen , I. Ilyin

New information on the relations between the Galactic disks, the halo, and satellite galaxies is being obtained from elemental abundances of stars having metallicities in the range -1.5 < [Fe/H] < -0.5. The first results for a sample of 26…

天体物理学 · 物理学 2015-05-13 Poul E. Nissen , William J. Schuster

The present study of spectra of twelve metal-rich cool dwarf stars, carefully selected in order to cover a range of temperatures (~4400 - 6000 K), is a follow up on Feltzing & Gustafsson (1998, A&AS 129, 237) with the aim to understand the…

天体物理学 · 物理学 2007-05-23 P. Thoren , S. Feltzing

We have performed a differential, line-by-line, chemical abundance analysis, ultimately relative to the Sun, of nine very metal-poor main sequence halo stars, near [Fe/H]=$-$2 dex. Our abundances range from…

太阳与恒星天体物理 · 物理学 2017-04-05 Erin O'Malley , Andrew McWilliam , Brian Chaboyer , Ian Thompson

Aims. This study aims to determine the level and constancy of the Spite plateau as definitively as possible from homogeneous high-quality VLT-UVES spectra of 19 of the most metal-poor dwarf stars known. Methods. Our high-resolution (R ~…

A non-LTE analysis of C I lines at 1.068-1.069 micron was carried out for selected 46 halo/disk stars covering a wide metallicity range (-3.7 <[Fe/H]< +0.3), based on the spectral data collected with IRCS+AO188 of the Subaru Telescope, in…

太阳与恒星天体物理 · 物理学 2015-06-15 Yoichi Takeda , Masahide Takada-Hidai

Sulfur abundances are derived for a sample of ten B main-sequence star members of the Orion association. The analysis is based on LTE plane-parallel model atmospheres and non-LTE line formation theory by means of a self-consistent spectrum…

太阳与恒星天体物理 · 物理学 2015-05-14 Simone Daflon , Katia Cunha , Ramiro de la Reza , Jon Holtzman , Cristina Chiappini

The aim of this work is to determine abundances of neutron-capture elements for thin- and thick-disc F, G, and K stars in several sky fields near the north ecliptic pole and to compare the results with the Galactic chemical evolution…

We discuss oxygen and iron abundance patterns in K and M red-giant members of the Galactic bulge and in the young and massive M-type stars inhabiting the very center of the Milky Way. The abundance results from the different bulge studies…

天体物理学 · 物理学 2009-11-13 K. Cunha , V. Smith , K. Sellgren , R. Blum , S. Ramirez , D. Terndrup

The main atmospheric parameters and abundances of the iron group elements (vanadium, chromium, iron, cobalt and nickel) are determined for 62 red giant "clump" stars revealed in the Galactic field by the Hipparcos orbiting observatory. The…

太阳与恒星天体物理 · 物理学 2015-05-19 E. Puzeras , G. Tautvaisiene , J. G. Cohen , D. F. Gray , S. J. Adelman , I. Ilyin , Y. Chorniy

We examine the distribution of the [O/Fe] abundance ratio in stars across the Galactic disk using H-band spectra from the Apache Point Galactic Evolution Experiment (APOGEE). We minimize systematic errors by considering groups of stars with…

An abundance analysis is reported of 58 K giants identified by Famaey et al. (2005) as highly probable members of the Hercules stream selected from stars north of the celestial equator in the Hipparcos catalogue. The giants have…

星系天体物理 · 物理学 2016-05-16 P. Ramya , Bacham E. Reddy , David L. Lambert , M. M. Musthafa

Silicon abundances were determined by applying the spectrum-fitting technic to the Si II doublet lines at 6347 and 6371A for a sample of 120 main-sequence stars in the T_eff range of ~7000-14000K (comprising not only normal stars but also…

太阳与恒星天体物理 · 物理学 2024-07-10 Yoichi Takeda

We performed an extensive non-LTE analysis of the neutral sodium lines of Na {\sc i} 5683/5688, 5890/5896, 6154/6161, and 8183/8195 for disk/halo stars of F--K type covering a wide metallicity range ($-4 \la$ [Fe/H] $\la 0.4$), based on our…

天体物理学 · 物理学 2014-10-13 Yoichi Takeda , Gang Zhao , Masahide Takada-Hidai , Yu-Qin Chen , Yu-ji Saito , Hua-Wei Zhang

In the last decade, the available measurements of fluorine abundance have increased significantly, providing additional information on the chemical evolution of our Galaxy and details on complex stellar nucleosynthesis processes. However,…

We have performed a detailed oxygen abundance analysis of 23 metal-poor (-3.0<[Fe/H]<-0.3) unevolved halo stars and one giant through the OH bands in the near UV, using high-resolution echelle spectra. Oxygen is found to be overabundant…

天体物理学 · 物理学 2009-10-30 G. Israelian , R. Garcia Lopez , R. Rebolo

In the framework of an ESO Large Programme high quality spectra of 70 very metal-poor dwarfs and giants were obtained with the VLT-UVES combination. This paper reports the detailed analyses of the 35 giants of the sample. At the exception…

[ABRIDGED] We determine Li abundances for a well-studied sample of 714 F and G dwarf, turn-off, and subgiant stars in the solar neighbourhood. The analysis is based on line synthesis of the Li line at 6707 {\AA} in high-resolution and high…

星系天体物理 · 物理学 2018-08-01 Thomas Bensby , Karin Lind

We present atmospheric parameters and iron abundances derived from high-resolution spectra for three samples of dwarf stars: stars which are known to host close-in giant planets (CGP), stars for which radial velocity data exclude the…

天体物理学 · 物理学 2009-11-10 U. Heiter , R. E. Luck