The White Dwarf Cooling Sequence of NGC 188
American Astronomical Society Meeting Abstracts
White dwarf cooling sequences represent one of the few ways in which we can determine ages of Galactic components such as the disk, the halo, and globular star clusters. These age measurements rely heavily on theoretical cooling models, many of which disagree by as much as a few gigayears for the coolest white dwarfs. Further, observations of the white dwarf sequence in the super metal-rich open cluster NGC 6791 have found evidence for two white dwarf cooling sequences; the debate over the interpretation of these two populations is unsettled. We have undertaken a study of the white dwarf sequence of the solar-metallicity, 7-Gyr old open cluster NGC 188 in order to address the white dwarf model uncertainties and to see if the cooling sequence of NGC 6791 is unique. We present initial results of deep HST WFPC2 imaging of NGC 188 and discuss the implications of its white dwarf population.
Physics and Astronomy
Williams, Kurtis A.; Jeffery, E.; von Hippel, T.; and De Gennaro, S., "The White Dwarf Cooling Sequence of NGC 188" (2009). Faculty Publications. 141.