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dc.contributor.authorMeléndez, Jorgept_BR
dc.contributor.authorRamírez, Ivánpt_BR
dc.contributor.authorKarakas, Amanda I.pt_BR
dc.contributor.authorYong, Davidpt_BR
dc.contributor.authorMonroe, TalaWanda Rosept_BR
dc.contributor.authorBedell, Meganpt_BR
dc.contributor.authorBergemann, Mariapt_BR
dc.contributor.authorAsplund, Martinpt_BR
dc.contributor.authorMaia, Marcelo Tuccipt_BR
dc.contributor.authorBean, Jacob L.pt_BR
dc.contributor.authorNascimento Júnior, José Dias dopt_BR
dc.contributor.authorBazot, Michaelpt_BR
dc.contributor.authorAlves-Brito, Alanpt_BR
dc.contributor.authorFreitas, Fabrício Catani dept_BR
dc.contributor.authorCastro, Matthieu Sébastienpt_BR
dc.date.accessioned2014-12-11T02:15:54Zpt_BR
dc.date.issued2014pt_BR
dc.identifier.issn0004-637Xpt_BR
dc.identifier.urihttp://hdl.handle.net/10183/108037pt_BR
dc.description.abstractWe study with unprecedented detail the chemical composition and stellar parameters of the solar twin 18 Sco in a strictly differential sense relative to the Sun. Our study is mainly based on high-resolution (R ∼ 110,000), high signal-to-noise ratio (800–1,000) Very Large Telescope UVES spectra, which allow us to achieve a precision of about 0.005 dex in differential abundances. The effective temperature and surface gravity of 18 Sco are Teff = 5823 ± 6 K and log g = 4.45 ± 0.02 dex, i.e., 18 Sco is 46 ± 6 K hotter than the Sun and log g is 0.01 ± 0.02 dex higher. Its metallicity is [Fe/H] = 0.054 ± 0.005 dex, and its microturbulence velocity is +0.02 ± 0.01 km s−1 higher than solar. Our precise stellar parameters and differential isochrone analysis show that 18 Sco has a mass of 1.04 ± 0.02M and that it is ∼1.6 Gyr younger than the Sun.We use precise High Accuracy Radial velocity Planet Searcher (HARPS) radial velocities to search for planets, but none are detected. The chemical abundance pattern of 18 Sco displays a clear trend with condensation temperature, thus showing higher abundances of refractories in 18 Sco than in the Sun. Intriguingly, there are enhancements in the neutron-capture elements relative to the Sun. Despite the small element-to-element abundance differences among nearby n-capture elements (∼0.02 dex), we successfully reproduce the r-process pattern in the Solar System. This is independent evidence for the universality of the r process. Our results have important implications for chemical tagging in our Galaxy and nucleosynthesis in general.en
dc.format.mimetypeapplication/pdf
dc.language.isoengpt_BR
dc.relation.ispartofThe astrophysical journal. Bristol. Vol. 791, no. 1 (Aug. 2014), 14, 14 p.pt_BR
dc.rightsOpen Accessen
dc.subjectStars: abundancesen
dc.subjectComposicao estelarpt_BR
dc.subjectStars: AGB and post-AGBen
dc.subjectMovimento estelarpt_BR
dc.subjectStars: fundamental parametersen
dc.subjectEspectros estelarespt_BR
dc.subjectTurbulênciapt_BR
dc.subjectSun: abundancesen
dc.subjectCondensaçãopt_BR
dc.subjectEspectros ultravioletapt_BR
dc.subjectNucleosíntesept_BR
dc.subjectCaptura radioativa de nêutronspt_BR
dc.title18 Sco : a solar twin rich in refractory and neutron-capture elements, implications for chemical taggingpt_BR
dc.typeArtigo de periódicopt_BR
dc.identifier.nrb000944099pt_BR
dc.type.originEstrangeiropt_BR


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