Spectral matching for abundances of 848 stars of the giant branches of the globular cluster ω Centauri

Abstract

We present the effective temperatures, surface gravities and abundances of iron, carbon and barium of 848 giant branch stars, of which 557 also have well-defined nitrogen abundances, of the globular cluster ω Centauri. This work used photometric sources and lower resolution spectra for this abundance analysis. Spectral indices were used to estimate the oxygen abundance of the stars, leading to a determination of whether a particular star was oxygen-rich or oxygen-poor. The 557-star subset was analyzed in the context of evolutionary groups, with four broad groups identified. These groups suggest that there were at least four main four periods of star formation in the cluster. The exact order of these star formation events is not yet understood. These results compare well with those found at higher resolution and show the value of more extensive lower resolution spectral surveys. They also highlight the need for large samples of stars when working with a complex object like ω Cen.

12 pages, 14 figures, accepted for publication in MNRAS

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Cited by in corpus (11)

• The GALAH Survey: Observational Overview and Gaia DR1 companion
• Nucleosynthesis in helium-enriched asymptotic giant branch models: Implications for Heavy Element Enrichment in Omega Centauri
• The GALAH Survey: Chemically tagging the Fimbulthul stream to the globular cluster $\omega$ Centauri
• Blue straggler masses from pulsation properties. II. Topology of the Instability Strip
• A Nitrogen-Enhanced Metal-Poor star discovered in the globular cluster ESO280-SC06
• Stellar populations in $\omega$ Centauri: a multivariate analysis
• Helium Enhancement in the Metal Rich Red Giants of Omega Centauri
• Discovery of relatively hydrogen-poor giants in the Galactic globular cluster Omega Centauri
• High resolution spectroscopy of the relatively hydrogen-poor metal rich giants in the globular cluster Omega Centauri
• Omega Centauri: weak MgH-band in red giants directly trace the helium content
• Disruption of a Giant: Spectroscopic Identification of Members in the Periphery and Tidal Tails of $\omega$ Centauri