The temporal evolution of neutron-capture elements in the Galactic discs
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2018Autor
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Abstract
Important insights into the formation and evolution of the Galactic disc(s) are contained in the chemical compositions of stars.We analysed high-resolution and high signal-to-noise HARPS spectra of 79 solar twin stars in order to obtain precise determinations of their atmospheric parameters, ages (σ ∼0.4 Gyr) and chemical abundances (σ <0.01 dex) of 12 neutron-capture elements (Sr, Y, Zr, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd and Dy). This valuable data set allows us to study the [X/Fe]-age relations ...
Important insights into the formation and evolution of the Galactic disc(s) are contained in the chemical compositions of stars.We analysed high-resolution and high signal-to-noise HARPS spectra of 79 solar twin stars in order to obtain precise determinations of their atmospheric parameters, ages (σ ∼0.4 Gyr) and chemical abundances (σ <0.01 dex) of 12 neutron-capture elements (Sr, Y, Zr, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd and Dy). This valuable data set allows us to study the [X/Fe]-age relations over a time interval of ∼10 Gyr and among stars belonging to the thin and thick discs. These relations show that (i) the s-process has been the main channel of nucleosynthesis of n-capture elements during the evolution of the thin disc; (ii) the thick disc is rich in r-process elements which suggests that its formation has been rapid and intensive. In addition, the heavy (Ba, La, Ce) and light (Sr, Y, Zr) s-process elements revealed details on the dependence between the yields of AGB stars and the stellar mass or metallicity. Finally, we confirmed that both [Y/Mg] and [Y/Al] ratios can be employed as stellar clocks, allowing ages of solar twin stars to be estimated with an average precision of ∼0.5 Gyr. ...
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Monthly notices of the royal astronomical society. Oxford. Vol. 474, no. 2 (Feb. 2018), p. 2580-2593
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Artigos de Periódicos (39774)Ciências Exatas e da Terra (6068)
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