Abundances on the Main Sequence of Omega Centauri

TL;DR

This study measures the abundances of carbon, nitrogen, and strontium in main sequence stars of omega Centauri, revealing diverse patterns linked to different stellar enrichment sources, enhancing understanding of the cluster's chemical evolution.

Contribution

It provides detailed abundance ratios for main sequence stars in omega Centauri, highlighting multiple enrichment processes affecting the cluster's chemical history.

Findings

Variations in element abundances correlate with [Fe/H]

Evidence of enrichment from asymptotic giant branch stars

Possible influence of massive rotating stars on nitrogen levels

Abstract

Abundance ratios of carbon, nitrogen and strontium relative to iron, calculated using spectrum synthesis techniques, are given for a sample of main sequence and turnoff stars that belong to the globular cluster omega Centauri. The variations of carbon, nitrogen and/or strontium show several different abundance patterns as a function of [Fe/H]. The source of the enhancements/depletions in carbon, nitrogen and/or strontium may be enrichment from asymptotic giant branch stars of low (1--3 solar masses) and intermediate (3--8 solar masses) mass. Massive rotating stars which produce excess nitrogen without carbon and oxygen overabundances may also play a role. These abundances enable different contributors to be considered and incorporated into the evolutionary picture of omega Cen.