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The Y2 Isochrones Getting an Extra Dimension

Published online by Cambridge University Press:  01 April 2008

Sukyoung K. Yi
Affiliation:
Yonsei University, Department of Astronomy, Seoul 120-749, Korea email: yi@yonsei.ac.kr
Yong-Cheol Kim
Affiliation:
Yonsei University, Department of Astronomy, Seoul 120-749, Korea email: yi@yonsei.ac.kr
Pierre Demarque
Affiliation:
Yale University, Department of Astronomy, New Haven 06520-8101, CT, USA
Young-Wook Lee
Affiliation:
Yonsei University, Department of Astronomy, Seoul 120-749, Korea email: yi@yonsei.ac.kr
Sang-Il Han
Affiliation:
Yonsei University, Department of Astronomy, Seoul 120-749, Korea email: yi@yonsei.ac.kr
Do Gyun Kim
Affiliation:
Yonsei University, Department of Astronomy, Seoul 120-749, Korea email: yi@yonsei.ac.kr
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Abstract

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The Yonsei-Yale Isochrones have been widely used since its birth in 2001. We announce a major upgrade mainly making varieties of helium values available. The recent works on the globular clusters with extreme helium abundances have called for such a need. The new version of the Y2 Isochrones are available for [α/Fe] = 0 through 0.6, ΔYZ = 1.5 through 3.0, and extreme helium abundances (Y = normal 0.05, 0.1, 0.15, 0.2), and for 11 metallicity grids, with full capability of interpolation. The database will be powerful for making population models. Besides, the accuracy of the models on the lower main sequence has been substantially improved. We illustrate the major upgrades and demonstrate the power of the new grids.

Type
Contributed Papers
Copyright
Copyright © International Astronomical Union 2008

References

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