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Multiple population theory: The extreme helium population problem

Published online by Cambridge University Press:  01 October 2008

Sukyoung K. Yi
Sukyoung K. Yi*
Affiliation:
Yonsei University, Department of Astronomy, Seoul 120-749, Korea email: [email protected]
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Abstract

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The spreads in chemical abundances inferred by recent precision observations suggest that some or possibly all globular clusters can no longer be considered as simple stellar populations. The most striking case is ω Cen in the sense that its bluest main-sequence, despite its high metallicity, demands an extreme helium abundance of Y ≈ 0.4. I focus on this issue of “the extreme helium population problem” in this review.

Keywords

stars: abundancesAGB and post-AGBchemically peculiarevolution Hertzsprung-Russell diagramPopulation IIGalaxy: generalabundancesglobular clustersISM: abundances
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 4 , Symposium S258: The Ages of Stars , October 2008 , pp. 253 - 264
Copyright
Copyright © International Astronomical Union 2009

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