NOAO > Observing Info > Approved Programs > 2004B-0012
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NOAO > Observing Info > Approved Programs > 2004B-0012 |
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PI: Imants Platais, The Johns Hopkins University, imants@pha.jhu.edu
Address: Physics Department, 3400 N. Charles Street, Baltimore, MD 21218, USA
CoI: Terrence M. Girard, Yale University
CoI: William F. van Altena, Yale University
Title: Deep Astrometry of Old Open Clusters
Abstract:
We propose to complete the determination of cluster membership to
very faint magnitudes (V=20-22) for a set of five rich and old open
clusters as defined by the NSF-supported WIYN Open Cluster Study (WOCS).
For each cluster the proper-motion measurements will provide excellent
kinematic membership determinations for the entire cluster out to the
tidal radius or exceeding it. This astrometric study is a precursor to
the coordinated radial velocity survey of the same clusters conducted by
R. Mathieu (UW), which ultimately will provide three-dimensional
kinematic membership determination for the entire evolved cluster
population including a new class of the so-called sub-subgiants. With
ages from 2 Gyr to 8 Gyr, this set of clusters will allow us to examine
the evolution of the Present Day Mass Function toward the depletion of
low-mass stars and the evolution of binary populations. The new
absolute proper motions for these clusters in conjunction with other
space-phase coordinates will lead to a reliable determination of cluster
orbits in the Galaxy. Finally, the proposed BV photometry at the low-
mass end of the main sequence will provide additional leverage for
calibrating the theoretical temperature-color transformation over this
difficult range.
National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360
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NOAO > Observing Info > Approved Programs > 2004B-0012 |
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