The white dwarf cooling sequence in NGC 6791
Astrophysics
2009-11-10 v1
Abstract
In the old, populous, and metal-rich open cluster NGC 6791 we have used deep HST/ACS images to track the white dwarf cooling sequence down to m_F606W~28.5. The white dwarf luminosity function shows a well defined peak at m_F606W~27.4, and a bending to the blue in the color--magnitude diagram. If this peak corresponds to the end of the white dwarf cooling sequence the comparison with theoretical isochrones provides a cluster age estimate of ~2.4 Gyr, in sharp contrast with the age of 8--9 Gyr inferred from the main-sequence turn-off. If the end is at fainter magnitudes, the peak at m_F606W~27.4 is even more enigmatic. We discuss possible causes, none of them very convincing.
Keywords
Cite
@article{arxiv.astro-ph/0503397,
title = {The white dwarf cooling sequence in NGC 6791},
author = {L. R. Bedin and M. Salaris and G. Piotto and I. R. King and J. Anderson and S. Cassisi and Y. Momany and .},
journal= {arXiv preprint arXiv:astro-ph/0503397},
year = {2009}
}
Comments
11 pages, 3 figures. Accepted (2005 March 17) on ApJ Letter