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dc.contributor.authorCescutti, G.
dc.contributor.authorMorossi, C.
dc.contributor.authorFranchini, M.
dc.contributor.authorMarcantonio, P. Di
dc.contributor.authorChiappini, C.
dc.contributor.authorSteffen, M.
dc.contributor.authorValentini, M.
dc.contributor.authorFrançois, P.
dc.contributor.authorChristlieb, N.
dc.contributor.authorCortés, C.
dc.contributor.authorKobayashi, C.
dc.contributor.authorDepagne, E.
dc.date.accessioned2023-09-26T14:45:00Z
dc.date.available2023-09-26T14:45:00Z
dc.date.issued2021-10-01
dc.identifier.citationCescutti , G , Morossi , C , Franchini , M , Marcantonio , P D , Chiappini , C , Steffen , M , Valentini , M , François , P , Christlieb , N , Cortés , C , Kobayashi , C & Depagne , E 2021 , ' Barium lines in high-quality spectra of two metal-poor giants in the Galactic halo ' , Astronomy & Astrophysics , vol. 654 , A164 , pp. 1-12 . https://doi.org/10.1051/0004-6361/202141355
dc.identifier.issn1432-0746
dc.identifier.otherArXiv: http://arxiv.org/abs/2109.00277v1
dc.identifier.otherORCID: /0000-0002-4343-0487/work/143285562
dc.identifier.urihttp://hdl.handle.net/2299/26752
dc.description©2021 ESO. This is the accepted manuscript version of an article which has been published in final form at https://doi.org/10.1051/0004-6361/202141355
dc.description.abstractContext. Theoretical results showed the possibility that neutron capture elements were produced in the early Universe by two different sources: a frequent s-process source hosted by rotating massive stars, and a rare r-process source hosted most likely by neutron star mergers. The two sources produce barium with different isotopic compositions. Aims. We aim to investigate the lines of barium in two halo stars, HD 6268 and HD 4306. The spectra present an exquisite quality, both in terms of resolution (R > 100'000) and signal-to-noise (400). Due to hyperfine splitting (hfs) effects, barium lines are expected to show slightly different profiles depending on the barium isotopic fraction. Methods. We applied a standard local thermodynamic equilibrium synthesis of the barium lines. We compared the synthetic results assuming an s-process isotopic pattern or an r-process isotopic pattern for the two barium lines for each star that exhibited hfs. We also applied a methodology, less dependent on the accuracy of the theoretical Ba hfs structure, that transforms the lines of HD 4306 into those we would observe if its atmospheric parameter values (i.e. Teff, log g, micro- and macro-turbulence, Vsin i, and Ba abundance) were the same as those of HD 6268. Results. With both methods, our results show that the barium lines with hfs effects of HD 4306 are in agreement with an s-process composition and the lines in HD 6268 have a different profile, which is most likely linked to the presence of an r-process isotopic pattern. Conclusions. Two lines of barium of HD 6268 and HD 4306 seem to confirm the theoretical expectation that both r-process events and also s-process contribution by rotating massive stars have polluted the ancient halo of our Galaxy.en
dc.format.extent12
dc.format.extent428221
dc.language.isoeng
dc.relation.ispartofAstronomy & Astrophysics
dc.subjectastro-ph.SR
dc.subjectastro-ph.GA
dc.subjectGalaxy: halo
dc.subjectNuclear reactions, nucleosynthesis, abundances
dc.subjectStars: abundances
dc.subjectGalaxy: evolution
dc.subjectStars: rotation
dc.subjectAstronomy and Astrophysics
dc.subjectSpace and Planetary Science
dc.titleBarium lines in high-quality spectra of two metal-poor giants in the Galactic haloen
dc.contributor.institutionSchool of Physics, Astronomy and Mathematics
dc.contributor.institutionSchool of Humanities
dc.contributor.institutionCentre for Astrophysics Research (CAR)
dc.contributor.institutionSchool of Physics, Engineering & Computer Science
dc.contributor.institutionDepartment of Physics, Astronomy and Mathematics
dc.description.statusPeer reviewed
dc.identifier.urlhttp://www.scopus.com/inward/record.url?scp=85118423315&partnerID=8YFLogxK
rioxxterms.versionofrecord10.1051/0004-6361/202141355
rioxxterms.typeJournal Article/Review
herts.preservation.rarelyaccessedtrue


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