NOAO >   Observing Info >   Approved Programs >   2015A-0420

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Program Information for 2015A-0420


PI: Constantine Deliyannis, Indiana U., con@astro.indiana.edu
Address: , Bloomington, IN 47405-7105 USA

CoI: Barbara Anthony-Twarog, U. of Kansas
CoI: Bruce A Twarog, U. of Kansas
CoI: Jeffrey Cummings, Johns Hopkins U.
CoI: Aaron Steinhauer, State University of New York Geneseo

Title: Lithium in Clusters of Extrenely Opposite Metallicities: M92, versus NGC 6583 and 6791

Abstract: We continue our long-term study of the evolution of Li abundances in star clusters, with goal to improve our knowledge of poorly understood physical processes occurring inside solar-type stars, that are traced by Li, and to potentially provide constraints on the Big Bang Li abundance. This proposal includes clusters of extremely opposite metallicities: M92, one of the most metal-poor globular clusters, and NGC 6791 and NGC 6583, two of the three known most metal-rich open clusters. Our long- term study of M92 aims at identifying Li signatures in post-turnoff stars that might provide insight about Li depletion processes occurring during the MS (and thus constrain Big Bang Li). We have discovered a surprisingly high rate of Li-producing red giant stars in 2-Gyr-old open clusters NGC 6819 and 2158, and will survey the very rich OC NGC 6791 to learn whether if older (less massive) and more metal-rich giants also produce Li. NGC 6583's metallicity is known from only 2 stars of similar radial velocity. We will survey the photometrically apparent MS, TO, and giant members to seek confirmation of its claimed super-high metallicity, and contrast its younger (500-900Myr) Li-Teff patterns to those of NGC 6791 and (the third known super-metal-rich cluster) NGC 6253.

Program Type: ITAC

Scheduled Nights:
Run 1 (2015A):  WIYN/HYDR -- 4n on Jun 16 - Jun 19 2015


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



NOAO >   Observing Info >   Approved Programs >   2015A-0420

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