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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

Type I planetary nebulae (PNe) have high He/H and N/O ratios and are thought to be descendants of stars with initial masses of ~3-8Msun. These characteristics indicate that the progenitor stars experienced proton-capture nucleosynthesis at…

We present the first detailed and homogeneous analysis of the s-element content in Galactic carbon stars of N-type. Abundances of Sr,Y, Zr (low-mass s-elements, or ls) and of Ba, La, Nd, Sm and Ce (high-mass s-elements, hs) are derived…

Astrophysics · Physics 2009-11-07 C. Abia , I. Dominguez , R. Gallino , M. Busso , S. Masera , O. Straniero , P. de Laverny , B. Plez , J. Isern

Barium stars are chemically peculiar stars that exhibit enhancement of s-process elements. Chemical abundance analysis of barium stars can provide crucial clues for the study of the chemical evolution of the Galaxy. The Large Sky Area…

Solar and Stellar Astrophysics · Physics 2023-01-18 Fengyue Guo , Zhongding Cheng , Xiaoming Kong , Yatao Zhang , Yude Bu , Zhenping Yi , Bing Du , Jingchang Pan

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

With the availability of parallaxes provided by the Tycho-Gaia Astrometric Solution, it is possible to construct the Hertzsprung-Russell diagram (HRD) of barium and related stars with unprecedented accuracy. A direct result from the derived…

Solar and Stellar Astrophysics · Physics 2019-05-14 A. Escorza , H. M. J. Boffin , A. Jorissen , S. Van Eck , L. Siess , H. Van Winckel , D. Karinkuzhi , S. Shetye , D. Pourbaix

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

Bulk meteoritic data show isotopic variability of $slow$-neutron-capture ($s$-process) origin in a several elements heavier than Fe. One peculiar feature is that the lighter $s$-process elements (e.g., Zr and Mo) present larger anomalies…

Symbiotic stars (SySt) are binaries composed of a star in the later stages of evolution and a stellar remnant. The enhanced mass-loss from the giant drives interacting mass exchange and makes these systems laboratories for understanding…

Solar and Stellar Astrophysics · Physics 2017-01-04 Cezary Galan , Joanna Mikolajewska , Kenneth H. Hinkle , Richard R. Joyce

A new large sample of 895 s-process-rich candidates out of 454180 giant stars surveyed by LAMOST at low spectral resolution (R ~ 1800) has been reported by Norfolk et al. (2019; hereafter N19). We aim at confirming the s-process enrichment…

Solar and Stellar Astrophysics · Physics 2021-10-27 D. Karinkuzhi , S. Van Eck , A. Jorissen , A. Escorza , S. Shetye , T. Merle , L. Siess , S. Goriely , H. Van Winckel

We present the results of s-process nucleosynthesis calculations for AGB stars of different metallicities and initial masses. The computations were based on previously published stellar evolutionary models that account for the III dredge up…

Astrophysics · Physics 2009-10-05 M. Busso , R. Gallino , D. L. Lambert , C. Travaglio , V. V. Smith

Here we present the discovery of 895 s-process-rich candidates from 454,180 giant stars observed by the Large Sky Area Multi-Object Fibre Spectroscopic Telescope (LAMOST) using a data-driven approach. This sample constitutes the largest…

Context- S stars are late-type giants with spectra showing characteristic molecular bands of ZrO in addition to the TiO bands typical of M stars. Their overabundance pattern shows the signature of s-process nucleosynthesis. Intrinsic,…

Solar and Stellar Astrophysics · Physics 2019-05-01 Shreeya Shetye , Stephane Goriely , Lionel Siess , Sophie Van Eck , Alain Jorissen , Hans Van Winckel

This research forms part of an investigation into heavy element abundances in Asymptotic Giant Branch (AGB) stars in various stellar environments. Seven giant stars in the southern globular cluster 47 Tuc have been observed using the…

Astrophysics · Physics 2008-11-26 E. C. Wylie , P. L. Cottrell , C. A. Sneden , J. C. Lattanzio

The chemical abundances of the very metal-poor double-enhanced stars are excellent information for setting new constraints on models of neutron-capture processes at low metallicity. These stars are known as s+r stars, since they show…

Astrophysics · Physics 2009-11-11 Bo Zhang , Kun Ma , Guide Zhou

The heavy elements formed by neutron capture processes have an interesting history from which we can extract useful clues to and constraints upon both the characteristics of the processes themselves and the star formation and…

Astrophysics · Physics 2009-11-07 J. W. Truran , J. J. Cowan , C. A. Pilachowski , C. Sneden

Barium (Ba) stars form via mass-transfer in binary systems, and can subsequently interact with their white dwarf companion in a second stage of binary interaction. We used observations of main-sequence Ba systems as input for our…

Solar and Stellar Astrophysics · Physics 2018-09-17 Ana Escorza , Lionel Siess , Drisya Karinkuzhi , Henri M. J. Boffin , Alain Jorissen , Hans Van Winckel

The origin and evolution of neutron-capture elements in our Galaxy is poorly understood. In this work, we have attempted to understand the Galactic s-process nucleosynthesis using barium stars as probes. We have performed high resolution…

Solar and Stellar Astrophysics · Physics 2020-12-15 J. Shejeelammal , Aruna Goswami

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

Neutron-capture elements represent an important nucleosynthetic channel in the study of the Galactic Chemical Evolution of stellar populations. For stellar populations behind significant extinction, such as those in the Galactic Center and…

Astrophysics of Galaxies · Physics 2024-10-16 G. Nandakumar , N. Ryde , H. Hartman , G. Mace