Abundance gradients along the Galactic disc from chemical evolution models

TL;DR

This study models the chemical evolution of the Milky Way disc, focusing on abundance patterns and gradients at various distances, highlighting the importance of multiple processes in explaining observed data.

Contribution

It extends existing chemical evolution models to multiple Galactocentric distances and analyzes the combined effects of inside-out formation, gas flows, and star formation efficiency.

Findings

Inside-out formation is crucial but insufficient alone.

Radial gas flows and variable star formation efficiency are necessary.

Models align with APOGEE data and observed abundance gradients.

Abstract

In this paper, we study the formation and chemical evolution of the Milky Way disc with particular focus on the abundance patterns ([$\alpha$/Fe] vs. [Fe/H]) at different Galactocentric distances, the present-time abundance gradients along the disc and the time evolution of abundance gradients. We consider the chemical evolution models for the Galactic disc developed by Grisoni et al. (2017) for the solar neighborhood, both the two-infall and the one-infall ones, and we extend our analysis to the other Galactocentric distances. In particular, we examine the processes which mainly influence the formation of the abundance gradients: the inside-out scenario, a variable star formation efficiency, and radial gas flows. We compare our model results with recent abundance patterns obtained along the Galactic disc from the APOGEE survey and with abundance gradients observed from Cepheids, open clusters, HII regions and PNe. We conclude that the inside-out scenario is a key ingredient, but cannot be the only one to explain abundance patterns at different Galactocentric distances and abundance gradients. Further ingredients, such as radial gas flows and variable star formation efficiency, are needed to reproduce the observed features in the thin disc. The evolution of abundance gradients with time is also shown, although firm conclusions cannot still be drawn.