Abundance ratios \& ages of stellar populations in HARPS-GTO sample

TL;DR

This study analyzes heavy element abundances and ages of 1059 stars from the HARPS sample, revealing distinct chemical signatures among different Galactic populations and correlations with stellar ages.

Contribution

It provides a homogeneous analysis of heavy element abundances and ages, highlighting chemical distinctions and age-related trends across Galactic stellar populations.

Findings

Thick disk stars are chemically distinct for Zn and Eu.

High-alpha metal-rich stars show overabundances of Cu and Zn.

Several abundance ratios correlate with age in thin disk stars.

Abstract

In this work we present chemical abundances of heavy elements (Z$>$28) for a homogeneous sample of 1059 stars from HARPS planet search program. We also derive ages using parallaxes from Hipparcos and Gaia DR1 to compare the results. We study the [X/Fe] ratios for different populations and compare them with models of Galactic chemical evolution. We find that thick disk stars are chemically disjunt for Zn and Eu. Moreover, the high-alpha metal-rich population presents an interesting behaviour, with clear overabundances of Cu and Zn and lower abundances of Y and Ba with respect to thin disk stars. Several abundance ratios present a significant correlation with age for chemically separated thin disk stars (regardless of their metallicity) but thick disk stars do not present that behaviour. Moreover, at supersolar metallicities the trends with age tend to be weaker for several elements.