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Oxygen abundances of 67 dwarf stars in the metallicity range -1.6<[Fe/H]<-0.4 are derived from a non-LTE analysis of the 777 nm O I triplet lines. These stars have precise atmospheric parameters measured by Nissen and Schuster, who find…

Solar and Stellar Astrophysics · Physics 2015-06-11 I. Ramirez , J. Melendez , J. Chaname

Metal-poor components of dwarf galaxies around the Milky Way could be remnants of the building blocks of the Galactic halo structure. Low-mass stars that are currently observed as metal-poor stars are expected to have formed in chemically…

Solar and Stellar Astrophysics · Physics 2020-04-29 Misa Aoki , Wako Aoki , Patrick Francois

The abundances derived from planetary nebula emission show the presence of a metallicity gradient within the disk of the Milky Way up to Galactocentric distances of ~10 kpc, which are consistent with findings from studies of different types…

Astrophysics of Galaxies · Physics 2018-07-18 George J. S. Pagomenos , Jeronimo Bernard-Salas , Stuart R. Pottasch

We present tentative evidence for the existence of a dissolved star cluster at [Fe/H]=-2.7 in the Sextans dwarf spheroidal galaxy. We use the technique of chemical tagging to identify stars that are highly clustered in a multi-dimensional…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Torgny Karlsson , Joss Bland-Hawthorn , Ken Freeman , Joe Silk

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…

Astrophysics · Physics 2009-11-11 A. Ecuvillon , G. Israelian , N. C. Santos , N. G. Shchukina , M. Mayor , R. Rebolo

Context. Globular clusters are known to host multiple stellar populations, which are a signature of their formation process. The globular cluster E3 is one of the few low-mass globulars that is thought not to host multiple populations.…

Solar and Stellar Astrophysics · Physics 2018-09-12 L. Monaco , S. Villanova , G. Carraro , A. Mucciarelli , C. Moni Bidin

We present [C/Fe] and [N/Fe] abundance ratios and CH({\lambda}4300) and S({\lambda}3883) index measurements for 94 red giant branch (RGB) stars in the Sculptor dwarf spheroidal galaxy from VLT/VIMOS MOS observations at a resolving power R=…

Astrophysics of Galaxies · Physics 2016-01-06 C. Lardo , G. Battaglia , E. Pancino , D. Romano , T. J. L. de Boer , E. Starkenburg , E. Tolstoy , M. J. Irwin , P. Jablonka , M. Tosi

As part of our on-going project on the homogeneous chemical characterization of multiple stellar populations in globular clusters (GCs), we studied NGC 5634, associated to the Sagittarius dwarf spheroidal galaxy, using high-resolution…

We present the first comprehensive chemical study of a representative sample of 27 luminous red giant branch (RGB) stars belonging to Liller 1, a complex stellar system in the Galactic bulge. This study is based on medium-resolution…

A detailed study of the Star Formation History of the Sgr dSph galaxy is performed through the analysis of the data from the Sagittarius Dwarf Galaxy Survey (SDGS; Bellazzini, Ferraro & Buonanno 1999). Accurate statistical decontamination…

Astrophysics · Physics 2009-10-31 Michele Bellazzini , Francesco R. Ferraro , Roberto Buonanno

In spite of many observational efforts aiming to characterize the chemical evolution of our Galaxy, not much is known about the origin of fluorine (F). Models suggest that the F found in the Galaxy might have been produced mainly in three…

Astrophysics of Galaxies · Physics 2015-06-03 A. Recio-Blanco , P. de Laverny , C. Worley , N. C. Santos , C. Melo , G. Israelian

We further study the unusual trend we found at statistically significant levels in some globular clusters, including NGC 3201: a decreasing iron abundance in red giants towards the cluster centers. We first show that recently published new…

Astrophysics of Galaxies · Physics 2017-08-09 Valery V. Kravtsov

The metallicity distribution in the intracluster medium of the NGC 5044 group was studied up to 0.3 r_180 using the XIS instrument on board the Suzaku satellite. Abundances of O, Mg, Si, S, and Fe were measured with high accuracy. The…

Astrophysics · Physics 2008-11-03 Madoka Komiyama , Kosuke Sato , Ryo Nagino , Takaya Ohashi , Kyoko Matsushita

We present a study of elemental abundances in a sample of thirteen Blue Compact Dwarf (BCD) galaxies, using the $\sim$10--37$\mu$m high resolution spectra obtained with Spitzer/IRS. We derive the abundances of neon and sulfur for our sample…

The results of optical spectroscopy of H II regions in a sample of southern dwarf irregulars consisting of five dwarf galaxies in the Centaurus A group, four dwarfs in the Sculptor group, and eight additional dwarf galaxies are presented.…

Astrophysics · Physics 2009-11-07 Henry Lee , Eva K. Grebel , Paul Hodge

From chemical abundance analysis of stars in the Sagittarius dwarf spheroidal galaxy (Sgr), we conclude that the alpha-element deficiencies cannot be due to the Type Ia supernova (SNIa) time-delay scenario of Tinsley (1979). Instead, the…

Astrophysics of Galaxies · Physics 2015-06-17 Andrew McWilliam , George Wallerstein , Marta Mottini

Sulfur abundances derived from optical emission line measurements and ionization correction factors in planetary nebulae are systematically lower than expected for the objects' metallicities. We have carefully considered a large range of…

Astrophysics of Galaxies · Physics 2015-06-04 R. B. C. Henry , A. Speck , A. I. Karakas , G. J. Ferland , M. Maguire

We have observed five sulphur-bearing molecules in foreground diffuse molecular clouds lying along the sight-lines to five bright continuum sources. We have used the GREAT instrument on SOFIA to observe the 1383 GHz $^2\Pi_{3/2} J=5/2-3/2$…

Assuming that in the atmospheres of low-mass, metal-poor red giant stars, 1-D models based on LTE accurately predict the abundance of iron from Fe II, we derive a globular cluster metallicity scale based on the equivalent widths of Fe II…

Astrophysics · Physics 2009-07-28 Robert P. Kraft , Inese I. Ivans

NGC 362 is a non-common Type II Galactic globular cluster, showing a complex pseudo two-color diagram or 'chromosome map'. The clear separation of its stellar populations in the color-magnitude diagram and the distribution of the giant…

Astrophysics of Galaxies · Physics 2022-07-13 C. Vargas , S. Villanova , D. Geisler , C. Muñoz , L. Monaco , J. O'Connell , Ata Sarajedini
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