PI: Michael Briley, University of Wisconsin Oshkosh, firstname.lastname@example.org
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