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We investigate whether the anomalous elemental abundance patterns in some of the C-enhanced metal-poor-s+r (CEMP-r/s) stars are consistent with predictions of nucleosynthesis yields from the i-process, a neutron-capture regime at neutron…

Solar and Stellar Astrophysics · Physics 2015-07-28 L. Dardelet , C. Ritter , P. Prado , E. Heringer , C. Higgs , S. Sandalski , S. Jones , P. Denissenkov , K. Venn , M. Bertolli , M. Pignatari , P. Woodward , F. Herwig

In order to get a broader view of the s-process nucleosynthesis we study the abundance distribution of heavy elements of 35 barium stars and 24 CEMP-stars, including nine CEMP-s stars and 15 CEMP-r/s stars. The similar distribution of…

Solar and Stellar Astrophysics · Physics 2013-05-09 Wenyuan Cui , Jianrong Shi , Yuanyuan Geng , Caixia Zhang , Xiaoying Meng , Lang Shao , Bo Zhang

CEMP-s stars are very metal-poor stars with enhanced abundances of carbon and s-process elements. They form a significant proportion of the very metal-poor stars in the Galactic halo and are mostly observed in binary systems. This suggests…

Solar and Stellar Astrophysics · Physics 2014-03-05 Carlo Abate , Onno R. Pols , Robert G. Izzard , Amanda I. Karakas

Rotation was shown to have a strong impact on the structure and light element nucleosynthesis in massive stars. In particular, models including rotation can reproduce the primary nitrogen observed in halo extremely metal-poor (EMP) stars.…

The solar s-process abundances have been analyzed in the framework of a Galactic Chemical Evolution (GCE) model. The aim of this work is to implement the study by Bisterzo et al. (2014), who investigated the effect of one of the major…

Solar and Stellar Astrophysics · Physics 2017-01-25 S. Bisterzo , C. Travaglio , M. Wiescher , F. Käppeler , R. Gallino

A sample of 895 s-process-rich candidates has been found among the 454180 giant stars surveyed by LAMOST at low spectral resolution (R~1800). In a previous study, taking advantage of the higher resolution (R~86 000) offered by the the…

Solar and Stellar Astrophysics · Physics 2023-09-06 D. Karinkuzhi , S. Van Eck , S. Goriely , L. Siess , A. Jorissen , A. Choplin , A. Escorza , S. Shetye , H. Van Winckel , .

Cowan et al. (2021) review how roughly half the elements heavier than iron found in the Sun are produced by rapid neutron capture and half by slow neutron capture, the r- and s-processes. In the Sun, their relative contribution to…

Solar and Stellar Astrophysics · Physics 2021-06-23 Ruth C. Peterson

The enrichment of Pb in the Galaxy is followed in the framework of a detailed model of Galactic chemical evolution that already proved adequate to reproduce the chemical enrichment of O and of the elements from Ba to Eu. The stellar yields…

Astrophysics · Physics 2009-10-31 Claudia Travaglio , Roberto Gallino , Maurizio Busso , Raffaele Gratton

High-resolution spectroscopic observations of a hundred metal-poor Carbon and s-rich stars (CEMP-s) collected from the literature are compared with the theoretical nucleosynthesis models of asymptotic giant branch (AGB) presented in Paper I…

Solar and Stellar Astrophysics · Physics 2015-05-30 S. Bisterzo , R. Gallino , O. Straniero , S. Cristallo , F. Kaeppeler

Observations of elemental abundances in the Galaxy have repeatedly shown an intrinsic scatter as a function of time and metallicity. The standard approach to chemical evolution does not attempt to address this scatter in abundances since…

Astrophysics · Physics 2009-10-28 Craig J. Copi

Around half of the heavy elements in the universe are formed through the slow neutron capture (s-) process, which takes place in thermally pulsing asymptotic giant branch (AGB) stars with masses $1-6\;M_{\odot}$. The nucleosynthetic imprint…

Solar and Stellar Astrophysics · Physics 2024-11-06 A. J. Dimoff , C. J. Hansen , R. J. Stancliffe , B. Kubatova , I. Stateva , A. Kucinskas , V. Dobrovolskas

A significant fraction of all metal-poor stars are carbon-rich. Most of these carbon-enhanced metal-poor (CEMP) stars also show enhancement in elements produced mainly by the s-process (CEMP-s stars) and evidence suggests that the origin of…

Solar and Stellar Astrophysics · Physics 2016-07-13 E. Matrozis , R. J. Stancliffe

Several stars at the low-metallicity extreme of the Galactic halo show large spreads of [Pb/hs]. Theoretically, a s-process pattern should be obtained from an AGB star with fixed metallicity and initial mass. For the third dredge-up and the…

Astrophysics · Physics 2009-11-11 Wenyuan Cui , Bo Zhang

We study the s-process abundances at the epoch of the Solar-system formation as the outcome of nucleosynthesis occurring in AGB stars of various masses and metallicities. The calculations have been performed with the Galactic chemical…

Solar and Stellar Astrophysics · Physics 2013-11-22 S. Bisterzo , C. Travaglio , M. Wiescher , R. Gallino , F. Kaeppeler , O. Straniero , S. Cristallo , G. Imbriani , J. Goerres , R. J. deBoer

We analyze a set of published elemental abundances from a sample of CH stars which are based on high resolution spectral analysis of ELODIE and SUBARU/HDS spectra. All the elemental abundances were derived from local thermodynamic…

Solar and Stellar Astrophysics · Physics 2016-12-21 S. Cristallo , D. Karinkuzhi , A. Goswami , L. Piersanti , D. Gobrecht

Lead (Pb) is predominantly produced by the slow neutron-capture process (s process) in asymptotic giant branch (AGB) stars. In contrast to significantly enhanced Pb abundances predicted by low-mass, low-metallicity AGB-models, observations…

Solar and Stellar Astrophysics · Physics 2020-01-08 Melanie Hampel , Amanda I. Karakas , Richard J. Stancliffe , Bradley S. Meyer , Maria Lugaro

We report abundance estimates for neutron-capture elements, including lead (Pb), and nucleosynthesis models for their origin, in two carbon-rich, very metal-poor stars, LP625-44 and LP706-7. These stars are subgiants whose surface…

The origin of carbon-enhanced metal-poor (CEMP) stars plays a key role in characterising the formation and evolution of the first stars and the Galaxy since the extremely-poor (EMP) stars with [Fe/H] \leq -2.5 share the common features of…

Solar and Stellar Astrophysics · Physics 2017-03-29 Takuma Suda , Shimako Yamada , Masayuki Y. Fujimoto

We model the evolution of the abundances of light elements in carbon-enhanced metal-poor (CEMP) stars, under the assumption that such stars are formed by mass transfer in a binary system. We have modelled the accretion of material ejected…

Astrophysics · Physics 2009-11-13 Richard J. Stancliffe

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