NOAO >   Observing Info >   Approved Programs >   2017A-0423

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Program Information for 2017A-0423


PI: Constantine Deliyannis, Indiana U., con@astro.indiana.edu
Address: Astronomy Department, Swain Hall West 318, 727 E. 3rd Street, Bloomington, IN 47405-7105 USA

CoI: Bruce A Twarog, U. of Kansas
CoI: Barbara Anthony-Twarog, U. of Kansas
CoI: Qinghui Sun, Indiana U.
CoI: Aaron Steinhauer, State University of New York Geneseo

Title: Lithium Depletion in Solar Twins and in Metal-Poor Open Clusters

Abstract: We propose to continue our WIYN/Hydra survey of open cluster A(Li) (using the Li I line at 6708 as a probe of physical mechanisms occurring inside stars. Last year we completed data acquisition on two of the most metal-poor sample clusters, NGC 2204 and NGC 2243, and acquired most of the planned data for NGC 2506. We request 6 nights in February (see Exp Design) to complete NGC 2506 and to survey the subgiants and giants of NGC 2420 (which is slightly more metal-rich than NGC 2506). Note that we will continue to survey for Li-producing giants, a new class of stars that we discovered previously in both NGC 6819 and NGC 2158. We will also begin study of solar twins in the numerous newly found members (Geller et al. 2015) of M67, and to continue study of solar-twin and solar-type dwarfs in the iconic 7Gyr- old NGC 188. Analysis of the (partial) data acquired so far reveals a steeply declining Li-Teff trend near M_$, with some short- period binaries having preserved more Li, on average (as predicted). This phenomenon might provide a pathway to finding Li preservation in even older clusters, and provide hints about the Big Bang Li. It is probable that at least some of these projects will be part of Qinghui's PhD thesis.

Program Type: ITAC

Scheduled Nights:
Run 1 (2017A):  WIYN/HYDR -- 3n on Feb 22 - Feb 24 2017


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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