The ages of galactic globular clusters in the context of self-enrichment

Decressin, T., Baumgardt, H., Kroupa, P., Meynet, G. and Charbonnel, C. (2008). The ages of galactic globular clusters in the context of self-enrichment. In: Richard de Grijs and Jacques Lépine, The Ages of Stars. IAU Symposium 258: The Ages of Stars, Baltimore, MD, U.S.A., (265-274). 13-17 October 2008. doi:10.1017/S1743921309031913

Author Decressin, T.
Baumgardt, H.
Kroupa, P.
Meynet, G.
Charbonnel, C.
Title of paper The ages of galactic globular clusters in the context of self-enrichment
Conference name IAU Symposium 258: The Ages of Stars
Conference location Baltimore, MD, U.S.A.
Conference dates 13-17 October 2008
Proceedings title The Ages of Stars   Check publisher's open access policy
Journal name Proceedings of the International Astronomical Union   Check publisher's open access policy
Place of Publication Cambridge, U.K.
Publisher Cambridge University Press
Publication Year 2008
Year available 2009
Sub-type Fully published paper
DOI 10.1017/S1743921309031913
ISBN 9780521889896
ISSN 1743-9213
Editor Richard de Grijs
Jacques Lépine
Volume 4
Issue 258
Start page 265
End page 274
Total pages 10
Language eng
Formatted Abstract/Summary
A significant fraction of stars in globular clusters (about 70%-85%) exhibit peculiar chemical patterns, with strong abundance variations in light elements along with constant abundances in heavy elements. These abundance anomalies can be created in the H-burning core of a first generation of fast-rotating massive stars, and the corresponding elements are conveyed to the stellar surface thanks to rotational induced mixing. If the rotation of the stars is fast enough, this material is ejected at low velocity through a mechanical wind at the equator. It then pollutes the interstellar medium (ISM) from which a second generation of chemically anomalous stars can be formed. The proportion of anomalous stars to normal stars observed today depends on at least two quantities : (1) the number of polluter stars; (2) the dynamical history of the cluster, which may lose different proportions of first- and second-generation stars during its lifetime. Here we estimate these proportions, based on dynamical models for globular clusters. When internal dynamical evolution and dissolution due to tidal forces are accounted for, starting from an initial fraction of anomalous stars of 10% produces a present-day fraction of about 25%, still too small with respect to the observed 70-85%. In the case of gas expulsion by supernovae, a much higher fraction is expected to be produced. In this paper we also address the question of the evolution of the second-generation stars that are He-rich, and deduce consequences for the age determination of globular clusters.
Keyword Globular clusters: general
Stellar dynamics
Stellar evolution
Abundance Patterns
Gas Expulsion
Q-Index Code E1
Q-Index Status Provisional Code
Institutional Status Non-UQ
Additional Notes Publication date: 01 Oct 2008

Document type: Conference Paper
Sub-type: Ages of Stars
Collections: School of Mathematics and Physics
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