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A catalog compiling the parameters of 346 open clusters, including their metallicities, positions, ages, and velocities has been composed. The elements of the Galactic orbits for 272 of the clusters have been calculated. Spectroscopic…

Astrophysics of Galaxies · Physics 2016-02-17 V. A. Marsakov , M. L. Gozha , V. V. Koval' , L. V. Shpigel'

We investigate stellar elemental abundance patterns at z = 0 in 8 low-mass (M_* = 10^6 - 10^9 M_sun) galaxies in the Feedback in Realistic Environments (FIRE-2) cosmological simulations. Using magnesium (Mg) as a representative…

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 present chemical abundance analyses of sodium, iron-peak and neutron-capture elements for 97 kinematically selected thick disk, inner halo and outer halo stars with metallicities -3.3<[Fe/H]<-0.5. The main aim of this study is to examine…

Astrophysics of Galaxies · Physics 2015-06-16 Miho N. Ishigaki , Wako Aoki , Masashi Chiba

The supernova yields of several heavy elements including alpha-, iron-group, and r-process elements are obtained as a function of the mass of their progenitor main-sequence stars M_ms from the abundance patterns of extremely metal-poor…

Astrophysics · Physics 2009-10-31 Takuji Tsujimoto , Toshikazu Shigeyama

Understanding the abundance pattern of metal-poor stars and the production of heavy elements through various nucleosynthesis processes offers crucial insights into the chemical evolution of the Milky Way, revealing primary sites and major…

It is argued that the abundances of r-process related elements in stars with -3<[Fe/H]<-1 can be explained by the contributions of three sources. The sources are: the first generations of very massive (>100 solar masses) stars that are…

Astrophysics · Physics 2009-11-06 Y. -Z. Qian , G. J. Wasserburg

Aims: We describe our newly developed approach to detailed abundance analysis from integrated-light high-dispersion spectra of star clusters. As a pilot project, we measure abundances of several elements for three globular clusters (GCs) in…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 S. S. Larsen , J. P. Brodie , J. Strader

The compositions of stars are a critical diagnostic tool for many topics in astronomy such as the evolution of our Galaxy, the formation of planets, and the uniqueness of the Sun. Previous spectroscopic measurements indicate a large…

An overview of the sources for heavy elements in the early Galaxy is given. It is shown that observations of abundances in metal-poor stars can be used along with a basic understanding of stellar models to guide the search for the source of…

Astrophysics · Physics 2009-11-13 Yong-Zhong Qian

We present a homogeneous chemical abundance analysis of 16 elements in 190 metal-poor Galactic halo stars (38 program and 152 literature objects). The sample includes 171 stars with [Fe/H] < -2.5, of which 86 are extremely metal poor,…

We present a model to explain the wide range of abundances for heavy r-process elements (mass number A > 130) at low [Fe/H]. This model requires rapid star formation and/or an initial population of supermassive stars in the earliest…

Astrophysics · Physics 2009-10-31 G. J. Wasserburg , Y. -Z. Qian

Context. Elemental abundances are of prime importance to help us reconstruct the origin and evolution of stars and galaxies in our Universe. Sulfur abundances have not been as heavily studied as other elements, so some details regarding its…

Solar and Stellar Astrophysics · Physics 2020-02-26 Ana Rita Costa Silva , Elisa Delgado Mena , Maria Tsantaki

Low-metallicity stars preserve the signatures of the first stellar nucleosynthesis events in the Galaxy, as their surface abundances reflect the composition of the interstellar medium from which they were born. Aside from primordial Big…

Solar and Stellar Astrophysics · Physics 2025-03-25 Khalil Farouqi , Anna Frebel , Friedrich-Karl Thielemann

Aims. The Chemical Evolution of R-process Elements in Stars (CERES) project aims to provide a homogeneous analysis of a sample of metal-poor stars ([Fe/H]<-1.5). We present the stellar parameters and the chemical abundances of elements up…

Fully cosmological, high resolution N-Body + SPH simulations are used to investigate the chemical abundance trends of stars in simulated stellar halos as a function of their origin. These simulations employ a physically motivated supernova…

Astrophysics of Galaxies · Physics 2015-05-18 Adi Zolotov , Beth Willman , Alyson Brooks , Fabio Governato , David W. Hogg , Sijing Shen , James Wadsley

An increasing fraction of carbon-enhanced metal-poor (CEMP) stars is found as their iron abundance, [Fe/H], decreases below [Fe/H] = -2.0. The CEMP-s stars have the highest absolute carbon abundances, [C/H], and are thought to owe their…

Solar and Stellar Astrophysics · Physics 2016-03-21 C. J. Hansen , B. Nordstroem , T. T. Hansen , C. R. Kennedy , V. M. Placco , T. C. Beers , J. Andersen , G. Cescutti , C. Chiappini

We present a comprehensive analysis of the detailed chemical abundances for a sample of 11 metal-poor, very metal-poor and extremely metal-poor stars ([Fe/H] = -1.65 to [Fe/H] = -3.0) as part of the HESP-GOMPA (Galactic survey Of Metal Poor…

Ground- and space-based observations of stellar heavy element abundances are providing a clearer picture of the chemical evolution of the Galaxy. A large number of (r)apid and (s)low neutron capture process elements, including the first…

Astrophysics · Physics 2007-05-23 John J Cowan , Christopher Sneden , James W Truran , Debra L Burris

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
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