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dc.contributor.author | Mashonkina L. | |
dc.contributor.author | Vinogradova A. | |
dc.contributor.author | Ptitsyn D. | |
dc.contributor.author | Khokhlova V. | |
dc.contributor.author | Chernetsova T. | |
dc.date.accessioned | 2018-09-18T20:15:19Z | |
dc.date.available | 2018-09-18T20:15:19Z | |
dc.date.issued | 2007 | |
dc.identifier.issn | 1063-7729 | |
dc.identifier.uri | https://dspace.kpfu.ru/xmlui/handle/net/138011 | |
dc.description.abstract | We derived Sr, Y, Zr, and Ce abundances for a sample of 74 cool dwarfs and subgiants with iron abundances, [Fe/H], between 0.25 and -2.43. These estimates were obtained using synthetic spectra, assuming local thermodynamic equilibrium (LTE) for Y, Zr, and Ce, allowing for non-LTE conditions for Sr. We used high-resolution (λ/Δλ≈40 000 and 60 000) spectra with signal-to-noise ratios between 50 and 200. We find that the Zr/Y, Sr/Y, and Sr/Zr ratios for the halo stars are the same in a wide metallicity range (-2.43 ≤ [Fe/H] ≤ -0.90), within the errors, indicating a common origin for these elements at the epoch of halo formation. The Zr/Y ratios for thick-disk stars quickly decrease with increasing Ba abundance, indicating a lower rate of production of Zr compared to Y during active thick-disk formation. The thick-disk and halo stars display an increase in the [Zr/Ba] ratio with decreasing Ba abundance and a correlation of the Zr and Eu overabundances relative to Ba. The evolutionary behavior of the abundance ratios found for the thick-disk and halo stars does not agree with current models for the Galaxy's chemical evolution. The abundance ratios of Y and Zr to Fe and Ba for thin-disk stars, as well as the abundance ratios within each group, are, on average, solar, though we note a slight decrease of Zr/Ba and Zr/Y with increasing Ba abundance. These results provide evidence for a dominance of asymptotic-giant-branch stars in the enrichment of the interstellar medium in heavy elements during the thin-disk epoch, in agreement with the predictions of the nucleosynthesis theory for the main s-process component. © 2007 Pleiades Publishing, Ltd. | |
dc.relation.ispartofseries | Astronomy Reports | |
dc.title | Neutron-capture elements in halo, thick-disk, and thin-disk stars. Strontium, yttrium, zirconium, cerium | |
dc.type | Article | |
dc.relation.ispartofseries-issue | 11 | |
dc.relation.ispartofseries-volume | 51 | |
dc.collection | Публикации сотрудников КФУ | |
dc.relation.startpage | 903 | |
dc.source.id | SCOPUS10637729-2007-51-11-SID36649014952 |