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We present NLTE abundances and atmospheric parameters for three metal-poor stars ([Fe/H]<-2) in Coma Berenices ultra-faint dwarf galaxy (UFD). The derived results are based on new photometric observations obtained with the 2.5-m telescope…

Solar and Stellar Astrophysics · Physics 2018-12-05 Tatyana Sitnova , Lyudmila Mashonkina , Andrey Tatarnikov , Olga Voziakova , Marina Burlak , Yuriy Pakhomov

The primary objective of this study is to accurately determine the abundances of Cu, Sr, Y, Zr, Ba, La, and Ce in selected solar-type stars. This will allow us to establish observational abundance-metallicity and abundance-age relations and…

Solar and Stellar Astrophysics · Physics 2024-07-23 Valentina Sheminova , Martina Baratella , Valentina D'Orazi

Following the recent abundance measurements of Mg, Al, Ca, Fe, and Ni in the black hole X-ray binary XTE J1118+480 using medium-resolution Keck II/ESI spectra of the secondary star (Gonz\'alez Hern\'andez et al. 2006), we perform a detailed…

Ongoing surveys are in the process of measuring the chemical abundances in large numbers of stars, with the ultimate goal of reconstructing the formation history of the Milky Way using abundances as tracers. However, interpretation of these…

Astrophysics of Galaxies · Physics 2018-10-17 Lucia Armillotta , Mark R. Krumholz , Yusuke Fujimoto

We use detailed nucleosynthesis calculations and a realistic prescription for the environment of the first stars to explore the first episodes of chemical enrichment that occurred during the dark ages. Based on these calculations, we…

Astrophysics of Galaxies · Physics 2015-06-19 Ryan Cooke , Piero Madau

Elemental abundances of Sun-like stars are crucial for understanding the detailed properties of their planets. However, measuring elemental abundances in M stars is challenging due to their faintness and pervasive molecular features in…

Solar and Stellar Astrophysics · Physics 2024-08-28 Haiyang S. Wang , Sascha P. Quanz , Suvrath Mahadevan , Morgan Deal

We have compiled a sample of 699 stars from the recent literature with detailed chemical abundance information (spanning -4.2 < [Fe/H] < +0.3), and we compute their space velocities and Galactic orbital parameters. We identify members of…

Astrophysics · Physics 2009-11-13 Ian U. Roederer

We present new observations of copper and zinc abundances in 90 metal-poor stars, belonging to the metallicity range -3< [Fe/H] < -0.5. The present study is based on high resolution spectroscopic measurements collected at the Haute Provence…

Astrophysics · Physics 2009-11-07 T. V. Mishenina , V. V. Kovtyukh , C. Soubiran , C. Travaglio , M. Busso

We review the final stages of stellar evolution, supernova properties, and chemical yields as a function of the progenitor's mass M. (1) 8 - 10 Ms stars are super-AGB stars when the O+Ne+Mg core collapses due to electron capture. These…

Solar and Stellar Astrophysics · Physics 2009-05-14 Ken'ichi Nomoto , Shinya Wanajo , Yasuomi Kamiya , Nozomu Tominaga , Hideyuki Umeda

We introduce a stochastic halo formation model to compute the early chemical enrichment of the interstellar medium (ISM) of the halo. Contrary to 1-zone chemical evolution models, we are able to resolve local inhomogeneities in the ISM…

Astrophysics · Physics 2007-05-23 D. Argast , M. Samland , O. E. Gerhard , F. -K. Thielemann

Chemical elements in the hot medium permeating early-type galaxies, groups, and clusters make them an excellent laboratory for studying metal enrichment and cycling processes in the largest scales of the universe. Here, we report the…

Astrophysics of Galaxies · Physics 2023-08-10 Kotaro Fukushima , Shogo B. Kobayashi , Kyoko Matsushita

Context. Carbon, nitrogen, and oxygen are the most abundant elements throughout the universe, after hydrogen and helium. Studying these elements in low-metallicity stars can provide crucial information on the chemical composition in the…

We performed a uniform and detailed abundance analysis of 12 refractory elements (Na, Mg, Al, Si, Ca, Ti, Cr, Ni, Co, Sc, Mn and V) for a sample of 1111 FGK dwarf stars from the HARPS GTO planet search program. 109 of these stars are known…

Earth and Planetary Astrophysics · Physics 2015-06-05 V. Zh. Adibekyan , S. G. Sousa , N. C. Santos , E. Delgado Mena , J. I. Gonzalez Hernandez , G. Israelian , M. Mayor , G. Khachatryan

This paper presents the chemical abundance analysis of a sample of 27 red giant stars located in 4 popolous intermediate-age globular clusters in the Large Magellanic Cloud, namely NGC 1651, 1783, 1978 and 2173. This analysis is based on…

Astrophysics · Physics 2009-11-13 A. Mucciarelli , E. Carretta , L. Origlia , F. R. Ferraro

The evolution of chemical elements in a galaxy is linked to its star formation history. Variations in star formation history are imprinted in the relative abundances of chemical elements produced in different supernova events and asymptotic…

Astrophysics of Galaxies · Physics 2013-05-07 Edita Stonkutė , Gražina Tautvaišienė , Birgitta Nordström , Renata Ženovienė

We report the abundances of 30 elements in 23 metal-poor ([Fe/H] <-1.7) giants. These are based on 7774 equivalent widths and spectral synthesis of 229 additional lines. Hyperfine splitting is taken into account when appropriate. Our choice…

Astrophysics · Physics 2016-08-30 Jennifer A. Johnson

We calculate the mean evolution of the iron-peak abundance ratios [(Cr,Mn,Co,Zn)/Fe] in the Galaxy, using modern supernova and hypernova chemical yields and a Galactic Chemical Evolution code that assumes homogeneous chemical evolution. We…

Astrophysics of Galaxies · Physics 2020-07-01 J. J. Grimmett , Amanda I. Karakas , Alexander Heger , Bernhard Müller , Christopher West

We calculate the evolution of heavy element abundances from C to Zn in the solar neighborhood adopting our new nucleosynthesis yields. Our yields are calculated for wide ranges of metallicity (Z=0-Z_\odot) and the explosion energy (normal…

Astrophysics · Physics 2008-11-26 C. Kobayashi , H. Umeda , K. Nomoto , N. Tominaga , T. Ohkubo

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]…

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