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Related papers: The Gaia-ESO Survey: the origin and evolution of s…

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Abundance observations indicate the presence of rapid-neutron capture (i.e., r-process) elements in old Galactic halo and globular cluster stars. These observations demonstrate that the earliest generations of stars in the Galaxy,…

Astrophysics · Physics 2017-08-23 J. J. Cowan , C. Sneden

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

To better characterize the abundance patterns produced by the r-process, we have derived new abundances or upper limits for the heavy elements zinc (Zn), yttrium (Y), lanthanum (La), europium (Eu), and lead (Pb). Our sample of 161…

Solar and Stellar Astrophysics · Physics 2015-05-20 I. U. Roederer , J. J. Cowan , A. I. Karakas , K. -L. Kratz , M. Lugaro , J. Simmerer , K. Farouqi , C. Sneden

Context: Trumpler 23 is a moderately populated, intermediate-age open cluster within the solar circle at a Rgc ~6 kpc. It is in a crowded field very close to the Galactic plane and the color-magnitude diagram shows significant field…

We follow the Galactic enrichment of three easily observed light n-capture elements Sr,Y,and Zr.Input stellar yields have been first separated into their respective main and weak s-process,and r-process components.The s-process yields from…

Abundance observations indicate the presence of often surprisingly large amounts of neutron capture (i.e., s- and r-process) elements in old Galactic halo and globular cluster stars. These observations provide insight into the nature of the…

We have derived ages, metallicities and enhanced-element ratios [alpha/Fe] for a sample of 83 early-type galaxies essentially in groups, the field or isolated objects. The stellar population properties derived for each galaxy corresponds to…

From newly-obtained high-resolution, high signal-to-noise ratio spectra the abundances of the elements La and Eu have been determined over the stellar metallicity range -3<[Fe/H]<+0.3 in 159 giant and dwarf stars. Lanthanum is predominantly…

Astrophysics · Physics 2009-11-10 J. Simmerer , C. Sneden , J. J. Cowan , J. Collier , V. M. Woolf , J. E. Lawler

Studying the abundances in metal-poor globular clusters is crucial for understanding the formation of the Galaxy and the nucleosynthesis processes in the early Universe. We observed 13 red giant stars from the metal-poor globular cluster…

Solar and Stellar Astrophysics · Physics 2025-05-08 Avrajit Bandyopadhyay , Rana Ezzeddine , Vinicius M. Placco , Anna Frebel , David S Aguado , Ian U. Roederer

We explore the structure and star formation history of the open cluster NGC 2264 (~3 Myr). We combined spectroscopic data from the Gaia-ESO Survey (GES) with multi-wavelength photometry from the Coordinated Synoptic Investigation of NGC…

From a detailed elemental abundance analysis of 102 F and G dwarf stars we present abundance trends in the Galactic thin and thick disks for 14 elements (O, Na, Mg, Al, Si, Ca, Ti, Cr, Fe, Ni, Zn, Y, Ba, and Eu). Stellar parameters and…

Astrophysics · Physics 2007-05-23 T. Bensby , S. Feltzing , I. Lundström , I. Ilyin

Aim of this work is to determine C, N, and O abundances in stars of Galactic open clusters of the Gaia-ESO survey and to compare the observed abundances with those predicted by current stellar and Galactic evolution models. In this pilot…

Pismis 18 is a moderately populated, intermediate-age open cluster located within the solar circle at a Galactocentric distance of about 7 kpc. Few open clusters have been studied in detail in the inner disc region before the Gaia-ESO…

Atomic diffusion and mixing processes in stellar interiors influence the structure and the surface composition of stars. Some of these processes cannot yet be modelled from the first principles. This limits their applicability in stellar…

We investigate the enrichment in elements produced by the slow neutron-capture process ($s$-process) in the globular clusters M4 (NGC 6121) and M22 (NGC 6656). Stars in M4 have homogeneous abundances of Fe and neutron-capture elements, but…

Solar and Stellar Astrophysics · Physics 2014-10-13 Luke J. Shingles , Amanda I. Karakas , Raphael Hirschi , Cherie K. Fishlock , David Yong , Gary S. Da Costa , Anna F. Marino

We exploit the unique characteristics of a sample of open clusters (OCs) and field stars for which high-precision 7Li abundances and stellar parameters are homogeneously derived by the Gaia-ESO Survey (GES). We derive possibly undepleted…

We present new accurate abundances for five neutron-capture (Y, La, Ce, Nd, Eu) elements in 73 classical Cepheids located across the Galactic thin disk. Individual abundances are based on high spectral resolution (R ~ 38,000) and high…

We present radial velocities and chemical abundances for nine stars in the old, distant open clusters Be 18, Be 21, Be 22, Be 32, and PWM 4. For Be 18 and PWM 4, these are the first chemical abundance measurements. Combining our data with…

Astrophysics of Galaxies · Physics 2015-06-05 David Yong , Bruce W. Carney , Eileen D. Friel

Recently, several studies have shown that young, open clusters are characterised by a considerable over-abundance in their barium content. In particular, D'Orazi et al. (2009) reported that in some younger clusters [Ba/Fe] can reach values…

Solar and Stellar Astrophysics · Physics 2015-06-04 Valentina D'Orazi , Katia Biazzo , Silvano Desidera , Elvira Covino , Sergei M. Andrievsky , Raffaele G. Gratton

The enrichment history of heavy neutron-capture elements in the Milky Way disc provides fundamental information about the chemical evolution of our Galaxy and about the stellar sources that made those elements. In this work we give new…

Astrophysics of Galaxies · Physics 2019-02-13 T. Mishenina , M. Pignatari , T. Gorbaneva , S. Bisterzo , C. Travaglio , F. K. Thielemann , C. Soubiran