Traits for chemical evolution in solar twins: Trends of neutron-capture elements with stellar age

Abstract

The physical processes driving chemical evolution in the Milky Way can be probed using the distribution of abundances in low-mass FGK type stars in space phase at different times. During their final stages of evolution stars experience nucleosynthesis several times, each at different timescales and producing different chemical elements, so finding abundance ratios that have simple variations across cosmic times remains a challenge. Using the sample of 80 solar twins for which ages and abundances of 30 elements were measured with high precision by Bedell et al 2018, we searched for all possible abundance ratios combinations that show linear trends with age. We found 55 such ratios, all combining a neutron-capture element and another one produced by different nucleosynthesis channels. We recovered the ratios of [Y/Mg], [Ba/Mg] and [Al/Y] reported previously in the literature, and found that [C/Ba] had the largest dependency with age with a slope of $0.049\pm 0.003dex/Gyr$, imposing constraints on the magnitude of time dependency of abundance ratios in solar twins. Our results suggest using s-process elements, in lieu of Fe, as a reference for constraining chemical evolution models of the solar neighbourhood. Our study illustrates hows a large variety of chemical elements measured from high resolution spectra is key in facing current challenges in understanding the formation and evolution of our Galaxy.

Accepted by A&A Letters

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Cited by in corpus (6)

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• Chemical abundances of 1111 FGK stars from the HARPS GTO planet search program IV. Carbon and C/O ratios for Galactic stellar populations and planet hosts
• Detailed chemical compositions of planet hosting stars: I. Exploration of possible planet signatures
• Extended theoretical transition data in C I - IV
• Searching for new solar twins: The Inti survey for the Northern Sky
• Using heritability of stellar chemistry to reveal the history of the Milky Way