47 Tucanae: the Spectroscopic versus CMD Age Discrepancy

Bibcode
2002IAUS..207..610V
Vazdekis, Alexandre; Salaris, Maurizio; Arimoto, Nobuo; Rose, James A.
Bibliographical reference

Extragalactic Star Clusters, IAU Symposium 207, Held in Pucon, Chile March 12-16, 2001. Edited by D. Geisler, E.K. Grebel, and D. Minniti. San Francisco: Astronomical Society of the Pacific, 2002., p.610

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0
2002
Number of authors
4
IAC number of authors
0
Citations
0
Refereed citations
0
Description
We investigate the origin of the discrepancy between the age estimates based on the Color-Magnitude-Diagram and the integrated spectra of 47 Tuc. Using a newly defined Hγ age indicator, with unprecedented power to disentangle the degeneracy between age and metallicity, we confirm the very large spectroscopic age derived for this cluster. We explore a number of key parameters with potential to decrease the Balmer lines and show the necessity of turnoff stars with lower temperatures. We find that alpha-enhanced isochrones with atomic diffusion leads to a younger spectroscopic age in better agreement with the CMD age.
Type
Non-refereed

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