Chemical compositions of semi-regular variable red giants

TL;DR

This study analyzes the chemical compositions of semi-regular variable red giants using high-resolution spectra, revealing their abundance ratios are similar to normal red giants across different Galactic populations, indicating their potential photometric activity.

Contribution

It provides the first detailed chemical abundance analysis of semi-regular variable red giants, comparing their ratios to those of normal red giants across Galactic populations.

Findings

Abundance ratios of semi-regular variables are similar to normal red giants.

Semi-regular variables may be among the more photometrically active red giants.

Chemical compositions suggest similar evolutionary status across populations.

Abstract

A sample of warm low level semi-regular variables chosen from the General Catalogue of Variable Stars is studied for their chemical compositions by analysing high resolution optical spectra. The abundance ratios from Na/Fe to Eu/Fe displayed by these and previously analysed semi-regular variables are quite similar to ratios displayed by normal red giants across the Galactic thin and thick disks and halo populations in the solar neighbourhood suggesting from this perspective that the variables may be among the more photometrically active red giants.