NOAO >   Observing Info >   Approved Programs >   2016B-0632

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Program Information for 2016B-0632


PI: Constantine Deliyannis, Indiana U., con@astro.indiana.edu
Address:

CoI: Bruce Twarog, U. of Kansas
CoI: Barbara Anthony-Twarog, U. of Kansas

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 6708A) as a probe of physical mechanisms occurring inside stars. This past season 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 3 nights in January 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 which we discovered previously in both NGC 6819 and NGC 2158. If time permits, we will begin study of solar twins in the numerous newly found members (Geller et al. 2015) of M67. We request 3 nights in October 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 1Msol, with 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 (2016B):  WIYN/HYDR -- 4n on Dec 22 - Dec 23 2016, Jan 22 - Jan 24 2017
Run 2 (2016B):  WIYN/HYDR -- 3n on Sep 25 - Sep 27 2016


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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