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We present an abundance analysis based on high resolution spectra of 10 stars selected to span the full range in metallicity in the Ursa Minor dwarf spheroidal galaxy. We find [Fe/H] for the sample stars ranges from -1.35 to -3.10 dex and…

宇宙学与河外天体物理 · 物理学 2015-05-19 Judith G. Cohen , Wenjin Huang

Globular clusters (GCs) are sites of extremely efficient star formation, and recent studies suggest they significantly contributed to the early Milky Way's stellar mass build-up. Although their role has since diminished, GCs' impact on the…

We have derived elemental abundances of three field red horizontal branch stars using high-resolution (R$\simeq$ 45,000), high signal-to-noise ratio (S/N $\gtrsim$ 200) $H$ and $K$ band spectra obtained with the Immersion Grating Infrared…

We have collected spectra of about 2000 red giant branch (RGB) stars in 19 Galactic globular clusters (GC) using FLAMES@VLT (about 100 star with GIRAFFE and about 10 with UVES, respectively, in each GC). These observations provide an…

星系天体物理 · 物理学 2015-05-14 Eugenio Carretta , Angela Bragaglia , Raffaele Gratton , Valentina D'Orazi , Sara Lucatello

We present the abundances of Li, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Co, Ni, Zn, Sr, Y, Zr, and Ba in a wide metallicity range ($-2.8 \le$ [Fe/H] $\le -1.5$). Using the differential technique allowed us to obtain an unprecedented low…

太阳与恒星天体物理 · 物理学 2017-12-06 Henrique Reggiani , Jorge Meléndez , Chiaki Kobayashi , Amanda Karakas , Vinicius Placco

We present detailed chemical abundances for $>$20 elements in $\sim$30 globular clusters in M31. These results have been obtained using high resolution ($\lambda/\Delta\lambda\sim$24,000) spectra of their integrated light and analyzed using…

星系天体物理 · 物理学 2022-10-26 J. E. Colucci , R. A. Bernstein , J. Cohen

We numerically investigate abundance properties of the Galactic globular clusters (GCs) by adopting a new ``external pollution'' scenario. In this framework, GCs are assumed to originate in forming low-mass dwarfs embedded in dark matter…

天体物理学 · 物理学 2008-11-26 K. Bekki , S. W. Campbell , J. C. Lattanzio , J. E. Norris

We investigate the light-element behavior of red giant stars in Northern globular clusters (GCs) observed by the SDSS-III Apache Point Observatory Galactic Evolution Experiment (APOGEE). We derive abundances of nine elements (Fe, C, N, O,…

We explore the origin of the observed decline in [O/Fe] (and [Mg/Fe]) with Galactocentric distance for high-metallicity stars ([Fe/H] > -1.1), based on a sample of halo stars selected within the Apache Point Observatory Galactic Evolution…

We study the multiple populations of $\omega$ Cen by using the abundances of Fe, C, N, O, Mg, Al, Si, K, Ca, and Ce from the high-resolution, high signal-to-noise (S/N$>$70) spectra of 982 red giant stars observed by the SDSS-IV/APOGEE-2…

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=…

星系天体物理 · 物理学 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

In this paper we study the very early phases of the evolution of our Galaxy by means of a chemical evolution model which reproduces most of the observational constraints in the solar vicinity and in the disk. We have restricted our analysis…

天体物理学 · 物理学 2016-08-30 Cristina Chiappini , Francesca Matteucci , Timothy Beers , Ken'ichi Nomoto

We use our new, flux-calibrated stellar population model of absorption-line indices to derive ages, metallicities, and various element abundance ratios from integrated light spectroscopy of galactic globular clusters. The ages agree well…

宇宙学与河外天体物理 · 物理学 2015-05-20 Daniel Thomas , Jonas Johansson , Claudia Maraston

We review the properties of globular clusters which make them useful for studying the Galactic halo, Galactic chemical evolution, and the early stages of the formation of the Milky Way. We review the evidence that GCs have a chemical…

星系天体物理 · 物理学 2015-05-14 Judith G. Cohen

It is well known that metal-poor red giant branch (RGB) stars show variations in some elemental abundances, including carbon, due to the internal mixing accompanied by their own in situ CN cycle in the hydrogen burning shell. With our new…

星系天体物理 · 物理学 2023-06-28 Jae-Woo Lee

We compute the chemical evolution of the Galactic bulge in the context of an inside-out model for the formation of the Milky Way. The model contains updated stellar yields from massive stars. The main purpose of the paper is to compare the…

天体物理学 · 物理学 2009-11-13 Silvia K. Ballero , Francesca Matteucci , Livia Origlia , R. Michael Rich

For the first time, we present an extensive study of stars with individual non-local thermodynamic equilibrium (NLTE) abundances for 17 chemical elements from Li to Eu in a sample of stars uniformly distributed over the $-2.62 \le$ [Fe/H]…

Chlorine abundances are reported in 15 evolved giants and one M dwarf in the solar neighborhood. The Cl abundance was measured using the vibration-rotation 1-0 P8 line of H$^{35}$Cl at 3.69851 $\mu$m. The high resolution L-band spectra were…

太阳与恒星天体物理 · 物理学 2016-12-05 Z. G. Maas , C. A. Pilachowski , K. Hinkle

Recent observations have shown that a growing number of the most massive Galactic globular clusters contain multiple populations of stars with different [Fe/H] and neutron-capture element abundances. NGC 6273 has only recently been…

The FLAMES survey ``Na-O anti-correlation and HB" uncovered the modern standard for globular clusters (GCs), that is their ubiquitous multiple stellar populations (MPs) distinct by the abundance of proton-capture elements. That survey can…

太阳与恒星天体物理 · 物理学 2026-03-25 Eugenio Carretta