Oxygen, $\alpha$-element and iron abundance distributions in the inner part of the Galactic thin disc. II

TL;DR

This study analyzes the chemical abundances in a Cepheid star near the Galactic center, supporting the existence of a plateau in element distribution within 5 kpc, possibly due to dynamic effects like the Galactic bar.

Contribution

First measurement of chemical abundances in a Cepheid within 2.5 kpc of the Galactic center, confirming a plateau in abundance distribution in the inner thin disc.

Findings

Support for a plateau-like abundance distribution within 5 kpc of the Galactic center

Potential link between abundance flattening and decreased star formation rate

Implication of dynamic effects, such as the Galactic bar, on chemical distribution

Abstract

We have derived the abundances of 36 chemical elements in one Cepheid star, ASAS 181024--2049.6, located R$_{\rm G}= 2.53$ kpc from the Galactic center. This star falls within a region of the inner thin disc poorly sampled in Cepheids. Our spectral analysis shows that iron, magnesium, silicon, calcium and titanium LTE abundances in that star support the presence of a plateau-like abundance distribution in the thin disc within 5 kpc of the Galactic center, as previously suggested by \cite{Maret15}. If confirmed, the flattening of the abundance gradient within that region could be the result of a decrease in the star formation rate due to dynamic effects, possibly from the central Galactic bar.