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In massive stars (initial mass of > 9 solar masses), the weak s (slow neutron capture) process produces elements between Fe and Zr, enriching the Galaxy with these elements through core-collapse supernova explosions. The weak s-process…

Solar and Stellar Astrophysics · Physics 2025-12-01 Emma Kotar , Shuya Ota , Allyson Dewey , Joshua Millman , Lorenzo Roberti , Marco Pignatari

At present none of Galactic chemical evolution (GCE) models provides a self-consistent description of observed trends for all iron-peak elements with metallicity simultaneously. The question is whether the discrepancy is due to deficiencies…

Solar and Stellar Astrophysics · Physics 2015-05-14 Maria Bergemann , Thomas Gehren

Theoretical physical-chemical models for the formation of planetary systems depend on data quality for the Sun's composition, that of stars in the solar neighbourhood, and of the estimated "pristine" compositions for stellar systems. The…

The goal of the Open Cluster Chemical Abundances and Mapping (OCCAM) survey is to constrain key Galactic dynamic and chemical evolution parameters by the construction and analysis of a large, comprehensive, uniform data set of infrared…

We discuss chemical enrichments of ~4000 SDSS early-type galaxies using as tracers the element abundance ratios [C/Fe], [N/Fe], [O/Fe], [Mg/Fe], [Ca/Fe] and [Ti/Fe]. We utilise the stellar population models of absorption line indices from…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Jonas Johansson , Daniel Thomas , Claudia Maraston

The earliest phases of the chemical evolution of our Galaxy are analysed in the light of the recent VLT results (concerning abundance patterns in the most metal-poor stars of the Galactic halo) and of stellar nucleosynthesis calculations.…

Astrophysics · Physics 2009-11-10 Nikos Prantzos

Chemical abundances in the X-ray halos (also known as the intracluster medium, ICM) of clusters and groups of galaxies can be measured via prominent emission line features in their X-ray spectra. Elemental abundances are footprints of…

High Energy Astrophysical Phenomena · Physics 2018-12-19 Junjie Mao , J. de Plaa , J. S. Kaastra , Ciro Pinto , Liyi Gu , F. Mernier , Hong-Liang Yan , Yu-Ying Zhang , H. Akamatsu

CONTEXT: [ABRIDGED]. For the Milky Way bulge, there are currently essentially no measurements of carbon in un-evolved stars, hampering our abilities to properly compare Galactic chemical evolution models to observational data for this still…

Astrophysics of Galaxies · Physics 2021-12-01 T. Bensby , A. Gould , M. Asplund , S. Feltzing , J. Meléndez , J. A. Johnson , S. Lucatello , A. Udalski , J. C. Yee

Context. The MINCE (Measuring at Intermediate Metallicity Neutron-Capture Elements) project aims to provide high quality neutron-capture abundances measurements in several hundred stars at intermediate metallicity,-2.5 < [Fe/H] < -1.5. This…

We present spatially-resolved measurements of stellar age, [Fe/H], and [$\alpha$/Fe] in three ultra-massive ($\rm{log(M_{\ast}/M_{\odot})>11}$), compact ($\rm{R_e} \lesssim 2$ kpc) quiescent galaxies at $z\sim3.5$ using JWST/NIRSpec IFU…

We investigate the [X/Mg] abundances of 16 elements for 82,910 Galactic disk stars from GALAH+ DR3. We fit the median trends of low-Ia and high-Ia populations with a two-process model, which describes stellar abundances in terms of a prompt…

Astrophysics of Galaxies · Physics 2022-05-25 Emily J. Griffith , David H. Weinberg , Sven Buder , Jennifer A. Johnson , James W. Johnson , Fiorenzo Vincenzo

Context. Stellar ages are typically very difficult to estimate for field stars. New empirical methods, based on abundance ratios of chemical elements, are emerging and need to be calibrated. Aims. Our main aim is to contribute to revealing…

In a recent study, based on homogeneous barium abundance measurements in open clusters, a trend of increasing [Ba/Fe] ratios for decreasing cluster age was reported. We present here further abundance determinations, relative to four other…

Solar and Stellar Astrophysics · Physics 2015-05-28 E. Maiorca , S. Randich , M. Busso , L. Magrini , S. Palmerini

Massive stars are key sources of radiative, kinetic, and chemical feedback in the universe. Grids of massive star models computed by different groups each using their own codes, input physics choices and numerical approximations, however,…

Solar and Stellar Astrophysics · Physics 2015-06-23 Samuel Jones , Raphael Hirschi , Marco Pignatari , Alexander Heger , Cyril Georgy , Nobuya Nishimura , Chris Fryer , Falk Herwig

We present results from the first large-scale survey of neutron(n)-capture element abundances in planetary nebulae (PNe). This survey was motivated by the fact that a PN may be enriched in n-capture elements if its progenitor star…

Astrophysics · Physics 2007-08-10 N. C. Sterling , Harriet L. Dinerstein , T. R. Kallman

Metal-poor stars in the Galactic halo often show strong enhancements in carbon and/or neutron-capture elements. However, the Galactic bulge is notable for its paucity of carbon-enhanced metal-poor (CEMP) and/or CH-stars, with only two such…

Astrophysics of Galaxies · Physics 2019-02-13 A. Koch , M. Reichert , C. J. Hansen , M. Hampel , R. J. Stancliffe , A. Karakas , A. Arcones

Detailed chemical composition studies of stars with enhanced abundances of neutron-capture elements can provide observational constraints for neutron-capture nucleosynthesis studies and clues for understanding their contribution to the…

Solar and Stellar Astrophysics · Physics 2016-08-31 Upakul Mahanta , Drisya Karinkuzhi , Aruna Goswami , Kalpana Duorah

We study the sensitivity of presupernova evolution and supernova nucleosynthesis yields of massive stars to variations of the initial composition. We use the solar abundances from Lodders (2009), and compute two different initial stellar…

Solar and Stellar Astrophysics · Physics 2024-10-23 Christopher West , Alexander Heger , Benoit Cote , Lev Serxner , Haoxuan Sun

Growing interests in the chemical feature of r-process elements among nearby disk stars represented by the [Eu/Fe] vs. [Fe/H] diagram have sprouted since it can assess the origin of r-process elements through the comparison with theoretical…

Astrophysics of Galaxies · Physics 2019-06-26 Takuji Tsujimoto , Junichi Baba

We investigate the origin of the abundance variations observed among similarly aged F and G dwarfs in the local Galactic disk. We present arguments in support of combined infall of metal-deficient gas and sequential enrichment by successive…

Astrophysics · Physics 2008-02-03 Bob van den Hoek , Teije de Jong
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