2017/11/09 by Lorenzo Spina, L. Spina, Jorge Meléndez +14 · 4 citations
Earth and Planetary Sciences · Physics and Astronomy · #Astro and Planetary Science #Astronomy #Astrophysics #Chemical evolution #High-pressure geophysics and materials #Metallicity #Neutron #Neutron capture #Nuclear physics #Nucleosynthesis #Physics #Spectral line #Stars #Stellar nucleosynthesis #Stellar, planetary, and galactic studies #astro-ph.GA #astro-ph.SR #r-process #s-process
paper · pdf · doi:10.1093/mnras/stx2938
arxiv created 2017/11/09 · openalex publication_date 2017/11/20 · arxiv updated 2017/12/27 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
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.