Oxygen, {\alpha}-element and iron abundance distributions in the inner part of the Galactic thin disc

TL;DR

This study investigates elemental abundance distributions in the inner Galactic thin disc using Cepheids, revealing a plateau or positive gradient in element abundances from the Galactic center to about 5 kpc.

Contribution

It provides new abundance measurements in a poorly studied inner disc region and combines them with existing data to analyze radial abundance trends.

Findings

Abundance distributions show a plateau or positive gradient within 5 kpc of the Galactic center.

Oxygen abundance distribution exhibits a similar trend to other elements.

Results suggest a distinct chemical evolution in the inner Galactic thin disc.

Abstract

We derived elemental abundances in 27 Cepheids, the great majority situated within a zone of Galactocentric distances ranging from 5 to 7 kpc. One star of our sample, SU Sct, has a Galactocentric distance of about 3 kpc, and thus falls in a poorly investigated region of the inner thin disc. Our new results, combined with data on abundances in the very central part of our Galaxy taken from literature, show that iron, magnesium, silicon, sulfur, calcium and titanium LTE abundance radial distributions, as well as NLTE distribution of oxygen reveal a plateau-like structure or even positive abundance gradient in the region extending from the Galactic center to about 5 kpc.