The Age and Metallicity Relation of Omega Centauri

Abstract

We present a metallicity distribution based on photometry and spectra for 442 omega Cen cluster members that lie at the main sequence turnoff region of the color-magnitude diagram. This distribution is similar to that found for the red giant branch. The distribution shows a sharp rise to a mean of [Fe/H] = -1.7 with a long tail to higher metallicities. Ages have then been determined for the stars using theoretical isochrones enabling the construction of an age-metallicity diagram. Interpretation of this diagram is complicated by the correlation of the errors in the metallicities and ages. Nevertheless, after extensive Monte-Carlo simulations, we conclude that our data show that the formation of the cluster took place over an extended period of time: the most metal-rich stars in our sample ([Fe/H] ~ -0.6) are younger by 2-4 Gyrs than the most metal-poor population.

53 pages, 20 figures, 5 tables, accepted for publication in ApJ

References in corpus (11)

• Omega Centauri: The Population Puzzle Goes Deeper
• Metallicities on the Double Main Sequence of omega Centauri Imply Large Helium Enhancement
• Two distinct ancient components in the Sculptor Dwarf Spheroidal Galaxy: First Results from DART
• Super Helium-Rich Population and the Origin of Extreme Horizontal-Branch Stars in Globular Clusters
• The origin of the double main sequence in Omega Centauri: Helium enrichment due to gas fueling from its ancient host galaxy ?
• Accretion relicts in the solar neighbourhood: debris from omegaCen's parent galaxy
• Metallicities, relative ages and kinematics of stellar populations in omega Centauri
• Discovery of an anomalous Sub Giant Branch in the Color Magnitude Diagram of omega Centauri
• The extended star formation history of omega Centauri
• On the anomalous red giant branch of the globular cluster Omega Cen
• On the Kinematics of Tidal Debris from Omega Cen's Progenitor Galaxy

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