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We present a strictly line-by-line differential analysis of a moderately $r$-process-enhanced star ($r$-I: HD~107752) with respect to a strongly $r$-process-enhanced star ($r$-II: CS~31082-0001) to investigate the possible common origin of…

We report the detection of the Pb I 4057.8A line in the very metal-poor ([Fe/H]=-2.7), carbon-rich star, LP625-44. We determine the abundance of Pb ([Pb/Fe] = 2.65) and 15 other neutron-capture elements. The abundance pattern between Ba and…

Astrophysics · Physics 2009-10-31 W. Aoki , J. E. Norris , S. G. Ryan , T. C. Beers , H. Ando

We demonstrate that nucleosynthesis in rapid, high-entropy expansions of proton-rich matter from high temperature and density can result in a wider variety of abundance patterns than heretofore appreciated. In particular, such expansions…

Astrophysics · Physics 2009-11-10 G. C. Jordan , B. S. Meyer

We present the abundances of Li, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Co, Ni, Zn, Sr, Y, Zr, and Ba in a wide metallicity range ($-2.8 \le$ [Fe/H] $\le -1.5$). Using the differential technique allowed us to obtain an unprecedented low…

Solar and Stellar Astrophysics · Physics 2017-12-06 Henrique Reggiani , Jorge Meléndez , Chiaki Kobayashi , Amanda Karakas , Vinicius Placco

Barium stars are one of the important probes to understand the origin and evolution of slow neutron-capture process elements in the Galaxy. These are extrinsic stars, where the observed s-process element abundances are believed to have an…

Solar and Stellar Astrophysics · Physics 2020-10-15 J. Shejeelammal , Aruna Goswami , Partha Pratim Goswami , Rajeev Singh Rathour , Thomas Masseron

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

Compilations of abundances of Strontium and Barium in extremely metal-poor stars show that an apparent cutoff is observed for [Sr/Ba] at [Fe/H]$<$-3.6 and large fluctuations for [Fe/H]$>$-3.6 with a clear upper bound depending on…

Solar and Stellar Astrophysics · Physics 2015-06-15 Wako Aoki , Takuma Suda , Richard Boyd , Toshitaka Kajino , Michael Famiano

The main s-process taking place in low mass stars produces about half of the elements heavier than iron. It is therefore very important to determine the importance and impact of nuclear physics uncertainties on this process. We have…

Solar and Stellar Astrophysics · Physics 2018-06-28 G. Cescutti , R. Hirschi , N. Nishimura , J. W. den Hartogh , T. Rauscher , A. St. J. Murphy , S. Cristallo

Recently Lian et al. (2023), thanks to Gaia-ESO data, studied the chemical evolution of neutron-capture elements in the regime [Fe/H]>-1. We aim here to complement this study down to [Fe/H]=-3, and focus on Ba, Y, Sr, and abundance ratios…

Solar and Stellar Astrophysics · Physics 2023-11-10 G. Guiglion , M. Bergemann , N. Storm , J. Lian , G. Cescutti , A. Serenelli

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

Neutron star mergers (NSMs) are promising astrophysical sites for the rapid neutron-capture ("$r$-") process, but can their integrated yields explain the majority of heavy-element material in the Galaxy? One method to address this question…

Nuclear physics has a long and productive history of application to astrophysics which continues today. Advances in the accuracy and breadth of astrophysical data and theory drive the need for better experimental and theoretical…

Astrophysics · Physics 2017-08-23 Carl R. Brune

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

AGB stars are responsible for producing a variety of elements, including carbon, nitrogen, and the heavy elements produced in the slow neutron-capture process ($s$-elements). There are many uncertainties involved in modelling the evolution…

Solar and Stellar Astrophysics · Physics 2015-04-22 C. Abate , O. R. Pols , A. I. Karakas , R. G. Izzard

In a brief review of abundances neutron-capture elements (Z > ~30) in metal-poor halo stars, attention is called to their star-to-star scatter, the dominance of r-process synthesis at lowest metallicities, the puzzle of the lighter members…

Astrophysics · Physics 2016-11-03 C. Sneden , J. J. Cowan , J. W. Truran

Hans Bethe contributed in many ways to our understanding of the supernovae that happen in massive stars, but, to this day, a first principles model of how the explosion is energized is lacking. Nevertheless, a quantitative theory of…

Astrophysics · Physics 2008-11-26 S. E. Woosley , A. Heger

The abundance patterns of $r$-process-enhanced stars contain key information required to constrain the astrophysical site(s) of $r$-process nucleosynthesis, and to deepen our understanding of the chemical evolution of our Galaxy. In order…

Solar and Stellar Astrophysics · Physics 2021-03-31 Tian-Yi Chen , Jian-Rong Shi , Timothy C. Beers , Hong-Liang Yan , Qi Gao , Chun-Qian Li , Hai-Ning Li , Gang Zhao

We investigated the impact of uncertainties in neutron-capture and weak reactions (on heavy elements) on the s-process nucleosynthesis in low-mass stars using a Monte-Carlo based approach. We performed extensive nuclear reaction network…

Solar and Stellar Astrophysics · Physics 2020-01-08 G. Cescutti , R. Hirschi , N. Nishimura , T. Rauscher , J. den Hartogh , A. St. J. Murphy , S. Cristallo

A large sample of carbon enhanced metal-poor stars enriched in s-process elements (CEMP-s) have been observed in the Galactic halo. These stars of low mass (M ~ 0.9 Msun) are located on the main-sequence or the red giant phase, and do not…

Solar and Stellar Astrophysics · Physics 2015-05-18 S. Bisterzo , R. Gallino , O. Straniero , S. Cristallo , F. Kaeppeler

We present a new analysis of the abundances observed in extremely metal poor stars based on both a new generation of theoretical presupernova models and explosions of zero metallicity massive stars and a new abundance analysis of an…

Astrophysics · Physics 2007-05-23 Marco Limongi , Alessandro Chieffi