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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…

Solar and Stellar Astrophysics · Physics 2017-04-05 Erin O'Malley , Andrew McWilliam , Brian Chaboyer , Ian Thompson

We present the results of a detailed abundance analysis of one of the confirmed building blocks of the Milky Way stellar halo, a kinematically-coherent metal-poor stellar stream. We have obtained high resolution and high S/N spectra of 12…

Astrophysics of Galaxies · Physics 2015-05-14 Ian U. Roederer , Christopher Sneden , Ian B. Thompson , George W. Preston , Stephen A. Shectman

High resolution spectra of 34 halo population dwarf and subgiant stars have been obtained with VLT/UVES and used to derive sulphur abundances from the 8694.0, 8694.6 A and 9212.9, 9237.5 A SI lines. In addition, iron abundances have been…

Astrophysics · Physics 2009-11-10 P. E. Nissen , Y. Q. Chen , M. Asplund , M. Pettini

We present an abundance analysis based on high resolution spectra of 8 stars selected to span the full range in metallicity in the Draco dwarf spheroidal galaxy. We find [Fe/H] for the sample stars ranges from -1.5 to -3.0 dex. Combining…

Astrophysics of Galaxies · Physics 2009-08-05 Judith G. Cohen , Wenjin Huang

(Abridged) Recent spectroscopic surveys have begun to explore the Galactic disk system outside the solar neighborhood on the basis of large data samples. In this way, they provide valuable information for testing spatial and temporal…

From a detailed elemental abundance analysis of 102 F and G dwarf stars we present abundance trends in the Galactic thin and thick disks for 14 elements (O, Na, Mg, Al, Si, Ca, Ti, Cr, Fe, Ni, Zn, Y, Ba, and Eu). Stellar parameters and…

Astrophysics · Physics 2007-05-23 T. Bensby , S. Feltzing , I. Lundström , I. Ilyin

By measuring the elemental abundances of a star, we can gain insight into the composition of its initial gas cloud -- the formation site of the star and its planets. Planet formation requires metals, the availability of which is determined…

Earth and Planetary Astrophysics · Physics 2021-09-02 Jared R. Kolecki , Ji Wang , Jennifer A. Johnson , Joel C. Zinn , Ilya Ilyin , Klaus G Strassmeier

Minor accretion events with mass ratio M_sat : M_host ~ 1:10 are common in the context of LCDM cosmology. We use high-resolution simulations of Galaxy-analogue systems to show that these mergers can dynamically eject disk stars into a…

Astrophysics of Galaxies · Physics 2015-05-14 Chris W. Purcell , James S. Bullock , Stelios Kazantzidis

We describe observations and abundance analysis of a high-resolution, high-S/N survey of 168 stars, most of which are metal-poor dwarfs. We follow a self-consistent LTE analysis technique to determine the stellar parameters and abundances,…

Astrophysics · Physics 2009-10-31 Jon P. Fulbright

ABRIDGED: To compare the chemistries of stars in the Milky Way dSph galaxies with stars in the Galaxy, we have compiled a large sample of Galactic stellar abundances from the literature. As found in previous studies, the [alpha/Fe] ratios…

Astrophysics · Physics 2009-11-10 K. A. Venn , M. Irwin , M. D. Shetrone , C. A. Tout , V. Hill , E. Tolstoy

Motivated by the recently improved knowledge on the kinematic and chemical properties of the Galactic metal-poor stars, we present the numerical simulation for the formation of the Galactic stellar halo to interpret the observational…

Astrophysics · Physics 2009-10-31 Kenji Bekki , Masashi Chiba

We explore the elemental abundance features of metal-rich disk stars, highlighting the comparisons made with those of the recently revealed Galactic bulge stars. A similarity between two of the comparisons leads to a new theoretical picture…

Astrophysics · Physics 2009-11-13 Takuji Tsujimoto

We test the hypothesis that the classical and ultra-faint dwarf spheroidal satellites of the our Galaxy have been the building blocks of the Galactic halo by comparing their [O/Fe] and [Ba/Fe] vs. [Fe/H] patterns with the ones observed in…

Astrophysics of Galaxies · Physics 2018-08-22 E. Spitoni , F. Vincenzo , F. Matteucci , D. Romano

We highlight some results from our detailed abundance analysis study of 703 kinematically selected F and G dwarf stars in the solar neighbourhood. The analysis is based on spectra of high-resolution (R=45000 to 110000) and high…

Astrophysics of Galaxies · Physics 2015-05-30 T. Bensby , S. Feltzing

We derive a star catalogue generated from the images taken as part of the 37.5 sq. deg Millennium Galaxy Catalogue. These data, alone and together with colours gained from the Sloan Digital Sky Survey Early Data Release, allow the analysis…

Astrophysics · Physics 2009-11-10 David Lemon , Rosemary F. G. Wyse , Jochen Liske , Simon Driver , Keith Horne

Using the DR12 public release of APOGEE data, we show that thin and thick disk separate very well in the space defined by [$\alpha$/Fe], [Fe/H] and [C/N]. Thick disk giants have both higher [C/N] and higher [$\alpha$/Fe] than do thin disk…

Solar and Stellar Astrophysics · Physics 2015-09-03 T. Masseron , G. Gilmore

In this work we present chemical abundances of heavy elements (Z$>$28) for a homogeneous sample of 1059 stars from HARPS planet search program. We also derive ages using parallaxes from Hipparcos and Gaia DR1 to compare the results. We…

Solar and Stellar Astrophysics · Physics 2018-06-13 E. Delgado Mena , M. Tsantaki , V. Zh. Adibekyan , S. G. Sousa , N. C. Santos , J. I. González Hernández , G. Israelian

The accurate O, Mg and Fe abundances derived in previous papers of this series from a homogenous reanalysis of high quality data for a large sample of stars are combined with stellar kinematics in order to discuss the history of star…

Astrophysics · Physics 2007-05-23 Raffaele Gratton , Eugenio Carretta , Francesca Matteucci , Chris Sneden

A linear [Fe/H]-[O/H] relation is found for different stellar populations in the Galaxy (halo, thick disk, thin disk) from a data sample obtained in a recent investigation (Ram{\'\i}rez et al. 2013). These correlations support previous…

Astrophysics of Galaxies · Physics 2017-06-15 R. Caimmi

We used the ugr magnitudes of 1,437,467 F-G type main-sequence stars with metal abundance -2<[Fe/H]<+0.2 dex and estimated radial and vertical metallicity gradients for high Galactic-latitude fields (b>50) of the Milky Way Galaxy. The…

Astrophysics of Galaxies · Physics 2019-01-16 S. Tuncel Guctekin , S. Bilir , S. Karaali , O. Plevne , S. Ak