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Related papers: R-process and alpha-elements in the Galactic disk:…

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The astrophysical origin of the rapid neutron-capture process (r-process), which produces about half of the elements heavier than iron, remains uncertain. The oldest, most metal-poor stars preserve the chemical signatures of early…

Context. The measurement of $\alpha$-elements abundances provides a powerful tool to put constraints on chemical evolution and star formation history of galaxies. The majority of studies on the $\alpha$-element Sulfur (S) are focused on…

Astrophysics of Galaxies · Physics 2021-12-22 F. Lucertini , L. Monaco , E. Caffau , P. Bonifacio , A. Mucciarelli

Theories of thick disk formation can be differentiated by measurements of stellar elemental abundances. We have undertaken a study of metal-poor stars selected from the RAVE spectroscopic survey of bright stars to establish whether or not…

The atmospheric parameters and abundances of Mg, Si, Ca, and Ti have been determined for 20 stars using the Gaia DR2 parallaxes, high-resolution spectra, and the non-local thermodynamic equilibrium (non-LTE) line formation modeling. A…

Solar and Stellar Astrophysics · Physics 2019-09-04 Lyudmila Mashonkina , Maria Neretina , Tatyana Sitnova , Yuri Pakhomov

Photospheric abundances are presented for 27 elements from carbon to europium in 181 F-G dwarfs from a differential LTE analysis of high-resolution and high signal-to-noise spectra. Stellar $T_{\rm eff}$ were adopted from an infrared flux…

Astrophysics · Physics 2009-11-07 Bacham E. Reddy , Jocelyn Tomkin , David L. Lambert , Carlos Allende Prieto

We computed the spatial velocities and the galactic orbital elements using Hipparcos data for 77 nearest main-sequence F-G-stars with published the iron, magnesium, and europium abundances determined from high dispersion spectra and with…

Astrophysics · Physics 2009-11-10 T. V. Borkova , V. A. Marsakov

As an investigation of the origin of ``$\alpha$-poor'' halo stars, we analyze kinematic and abundance data for 73 intermediate metallicity stars ($-1 >$ [Fe/H] $\geq -2$) selected from Paper I of this series. We find evidence for a…

Astrophysics · Physics 2009-12-08 Jon P. Fulbright

Small stellar systems like dwarf galaxies are suggested to be the main building blocks of our Galaxy by numerical simulations in Lambda CDM models. The existence of star streams like Sagittarius tidal stream indicates that dwarf galaxies…

Solar and Stellar Astrophysics · Physics 2019-05-13 Qian-Fan Xing , Gang Zhao , Wako Aoki , Satoshi Honda , Hai-Ning Li , Miho N. Ishigaki , Tadafumi Matsuno

The abundances of iron and oxygen are homogeneously determined in a sample of 523 nearby (d<150 pc) FGK disk and halo stars with metallicities in the range -1.5<[Fe/H]<0.5. The oxygen abundances were inferred from a restricted non-LTE…

Astrophysics · Physics 2009-11-13 I. Ramirez , C. Allende Prieto , D. L. Lambert

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

In this paper we present an homogeneous analysis of photospheric abundances based on high-resolution spectroscopy of a sample of 182 barium stars and candidates. We determined atmospheric parameters, spectroscopic distances, stellar masses,…

Solar and Stellar Astrophysics · Physics 2016-04-27 D. B. de Castro , C. B. Pereira , F. Roig , E. Jilinski , N. A. Drake , C. Chavero , J. V. Sales Silva

Low-mass, variable, high-velocity stars are interesting study cases for many aspects of Galactic structure and evolution. Until recently, the only known high- or hyper-velocity stars were young stars thought to originate from the Galactic…

Solar and Stellar Astrophysics · Physics 2016-05-04 Camilla Juul Hansen , Robert Michael Rich , Andreas Koch , Siyi Xu , Andrea Kunder , Hans-Guenter Ludwig

The dominant site of production of $r$-process elements remains unclear despite recent observations of a neutron star merger. Observational constraints on the properties of the sites can be obtained by comparing $r$-process abundances in…

Astrophysics of Galaxies · Physics 2021-06-16 Tadafumi Matsuno , Yutaka Hirai , Yuta Tarumi , Kenta Hotokezaka , Masaomi Tanaka , Amina Helmi

We have compiled a large catalogue of metallicities and abundance ratios from the literature in order to investigate abundance trends of several alpha and iron peak elements in the thin disk and the thick disk of the Galaxy. The catalogue…

Astrophysics · Physics 2009-11-10 C. Soubiran , P. Girard

The present sample of nearby bulgelike dwarf stars has kinematics and metallicities characteristic of a probable inner disk or bulge origin. Ages derived by using isochrones give 10-11 Gyr for these stars and metallicities are in the range…

Astrophysics · Physics 2009-11-07 Luciana Pompeia , Beatriz Barbuy , Michel Grenon

Context. Barium (Ba) stars are dwarf and giant stars enriched in elements heavier than iron produced by the slow neutron-capture process (s process). They belong to binary systems where the primary star evolved through the asymptotic giant…

Solar and Stellar Astrophysics · Physics 2018-12-12 B. Cseh , M. Lugaro , V. D'Orazi , D. B. de Castro , C. B. Pereira , A. I. Karakas , L. Molnár , E. Plachy , R. Szabó , M. Pignatari , S. Cristallo

The aim of this work is to determine abundances of neutron-capture elements for thin- and thick-disc F, G, and K stars in several sky fields near the north ecliptic pole and to compare the results with the Galactic chemical evolution…

We compute the evolution of the abundances of barium and europium in the Milky Way and we compare our results with the observed abundances from the recent UVES Large Program "First Stars". We use a chemical evolution model which already…

Astrophysics · Physics 2007-05-23 G. Cescutti , P. Francois , F. Matteucci , R. Cayrel , M. Spite

We have obtained high-resolution, high signal-to-noise spectra for 899 F and G dwarf stars in the Solar neighbourhood. The stars were selected on the basis of their kinematic properties to trace the thin and thick discs, the Hercules…

Astrophysics of Galaxies · Physics 2015-05-13 T. Bensby , S. Feltzing

(Abbreviated) We present a detailed analysis of the space motions of 1203 solar-neighborhood stars with metal abundances [Fe/H] <= -0.6, on the basis of a recently revised and supplemented catalog of metal-poor stars selected without…

Astrophysics · Physics 2009-05-29 M. Chiba , T. C. Beers