The AMBRE Project: [Y/Mg] stellar dating calibration with Gaia
Laboratoire Lagrange (UMR7293), Université de Nice Sophia Antipolis, CNRS, Observatoire de la Côte d’Azur, BP 4229, 06304 Nice Cedex 4, France
2 Sydney Institute for Astronomy (SIfA), School of Physics, A28, The University of Sydney, NSW, 2006 Australia
3 Center of Excellence for Astrophysics in Three Dimensions (ASTRO-3D), Australia
4 Leibniz-Institut für Astrophysik Potsdam (AIP), 14482 Potsdam, Germany
Accepted: 8 November 2018
Chemical abundance dating methods open new paths for temporal evolution studies of the Milky Way stellar populations. In this paper, we use a high spectral resolution database of turn-off stars in the solar neighbourhood to study the age dependence of the [Y/Mg] chemical abundance ratio. Our analysis reveals a clear correlation between [Y/Mg] and age for thin disc stars of different metallicities, in synergy with previous studies of solar-type stars. In addition, no metallicity dependence with stellar age is detected, allowing us to use the [Y/Mg] ratio as a reliable age proxy. Finally, the [Y/Mg]–age relation presents a discontinuity between thin and thick disc stars around 9–10 Gyr. For thick disc stars, the correlation has a different zero point and probably a steeper trend with age, reflecting the different chemical evolution histories of the two disc components.
Key words: Galaxy: abundances / Galaxy: disk / Galaxy: stellar content / Galaxy: structure
© ESO 2019
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.