Barium Abundances in Cepheids

TL;DR

This study analyzes barium abundances in 270 Cepheids across the galactic disc to investigate radial gradients, finding that barium abundance remains constant regardless of galactocentric distance, which is a novel comprehensive analysis.

Contribution

First extensive analysis of barium abundance distribution in the galactic disc showing a zero gradient across a large galactocentric range.

Findings

Barium abundance shows no radial gradient in the galactic disc.

The distribution of barium is independent of galactocentric distance.

Comparison with other elements suggests unique behavior of barium.

Abstract

We derived the barium atmospheric abundances for a large sample of Cepheids, comprising 270 stars. The sample covers a large range of galactocentric distances, from about 4 to 15 kpc, so that it is appropriated to investigate the existence of radial barium abundance gradients in the galactic disc. In fact, this is the first time that such a comprehensive analysis of the distribution of barium abundances in the galactic disc is carried out. As a result, we conclude that the Ba abundance distribution can be characterized by a zero gradient. This result is compared with derived gradients for other elements, and some reasons are briefly discussed for the independence of the barium abundances upon galactocentric distances.