A chemical signature from fast-rotating low-metallicity massive stars: ROA 276 in omega Centauri

• Main Authors: Yong, David, Norris, John E, Da Costa, Gary S, Stanford, Laura M, Karakas, Amanda I, Shingles, Luke J, Hirschi, Raphael, Pignatari, Marco
• Format: Journal Article
• Language: English
• Published: 23-02-2017
• Subjects: Physics - Astrophysics of Galaxies; Physics - Solar and Stellar Astrophysics
• DOI: 10.48550/arxiv.1702.07087

We present a chemical abundance analysis of a metal-poor star, ROA 276, in
the stellar system omega Centauri. We confirm that this star has an unusually
high [Sr/Ba] abundance ratio. Additionally, ROA 276 exhibits remarkably high
abundance ratios, [X/Fe], for all elements from Cu to Mo along with normal
abundance ratios for the elements from Ba to Pb. The chemical abundance pattern
of ROA 276, relative to a primordial omega Cen star ROA 46, is best fit by a
fast-rotating low-metallicity massive stellar model of 20 Msun, [Fe/H] = -1.8,
and an initial rotation 0.4 times the critical value; no other nucleosynthetic
source can match the neutron-capture element distribution. ROA 276 arguably
offers the most definitive proof to date that fast-rotating massive stars
contributed to the production of heavy elements in the early Universe.