Tracing the Galactic thick disk to Solar metallicities

TL;DR

This study demonstrates that the Galactic thick disk extends to solar metallicities and underwent significant chemical enrichment over approximately 3 billion years, informing models of disk formation.

Contribution

It provides the first detailed elemental abundance analysis of thick disk stars reaching solar metallicities, constraining the formation and evolution of the Galactic disks.

Findings

Thick disk reaches at least solar metallicities.

Strong chemical enrichment occurred over ~3 Gyr.

The thick disk's formation ended around 8-9 Gyr ago.

Abstract

We show that the Galactic thick disk reaches at least solar metallicities, and that it experienced strong chemical enrichment during a period of ~3 Gyr, ending around 8-9 Gyr ago. This finding puts further constraints on the relation and interface between the thin and thick disks, and their formation processes. Our results are based on a detailed elemental abundance analysis of 261 kinematically selected F and G dwarf stars in the solar neighborhood: 194 likely members of the thick disk and 67 likely members of the thin disk, in the range -1.3<[Fe/H]<+0.4.