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arXiv · 0912.0257

The bottom of the white dwarf cooling sequence in the old open cluster NGC 2158

L. R. Bedin·M. Salaris·I. R. King·G. Piotto·J. Anderson·S. Cassisi
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Abstract

We use 10 orbits of Advanced Camera for Surveys observations to reach the end of the white dwarf cooling sequence in the solar-metallicity open cluster NGC 2158. Our photometry and completeness tests show that the end falls at magnitude m_F606W = 27.5 +/- 0.15, which implies an age between ~1.8 and ~2.0 Gyr, consistent with the age of 1.9 +/- 0.2 Gyr obtained from fits to the main-sequence turn-off. The faintest white dwarfs show a clear turn toward bluer colors, as predicted by theoretical isochrones.

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L. R. Bedin, M. Salaris, I. R. King, G. Piotto, J. Anderson, S. Cassisi. 2009-12-01. The bottom of the white dwarf cooling sequence in the old open cluster NGC 2158. https://doi.org/10.1088/2041-8205%2F708%2F1%2Fl32

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