NOAO > Observing Info > Approved Programs > 2010A-0388
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NOAO > Observing Info > Approved Programs > 2010A-0388 |
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PI: Michael Briley, University of Wisconsin Oshkosh, mike@maxwell.phys.uwosh.edu
Address: Department of Physics and Astronomy, 800 Algoma Blvd., Oshkosh, WI 54901, United States
CoI: Graeme Smith, UC Observatories/Lick Observatory
Title: Observational Constraints on Deep Mixing in Globular Red Giants
Abstract:
Over the past 30 years it has become apparent the Galactic globular
clusters are not chemically homogeneous collections of stars. The
observed abundance patterns in light elements (C, N, O, Na, Mg, and Al)
continue to defy explanation although it has become clear we are seeing
the effects of two processes - a deep mixing of CNO-cycle material to
the surface in evolving giants, and a primordial variation incorporated
early in the cluster history.
Here we focus on deep mixing, the efficiency of which is expected to
be a function of metallicity. We have recently tested this using a
handful of nearby clusters with the Lick 3-m and the results are
promising. However, the low and high metallicity ends of our sample are
poorly constrained. Here we request Hale DBSP time to secure the
observations necessary to robustly establish this relationship, which in
turn will provide observational constraints on competing theories of the
underlying mixing mechanism.
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 > 2010A-0388 |
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