NOAO >   Observing Info >   Approved Programs >   2012A-0315

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Proposal Information for 2012A-0315


PI: Jason Curtis, The Pennsylvania State University, jlc600@psu.edu
Address: Astronomy Department, 525 Davey Lab, University Park, PA 16802, USA

CoI: Jason Wright, The Pennsylvania State University
CoI: Steve Saar, Harvard-Smithsonian CfA

Title: Ruprecht 147: Membership and Chromospheric Activity Survey of the Closest Old Cluster

Abstract: Ruprecht 147 is a hitherto unappreciated open cluster that holds great promise as a standard in fundamental stellar astrophysics. We have confirmed membership for over 100 members, and our best isochrone fit places the cluster at ~250 pc and an age of ~2.8 Gyr, making it the closest old cluster by factor of 2 in each dimension. The K and M dwarfs of Ruprecht 147 will be the only old, single, cool dwarfs with known ages bright enough to admit close spectroscopic study. This proposal seeks 2 nights at CTIO with the 4-m Blanco telescope and Hydra multi-fiber spectrograph to complete a RV survey of the inner cluster, expand the membership down to the late-K and early-M dwarfs, and catalog the phase-averaged magnetic activity of the cluster via chromospheric \halpha emission. This work will also support an upcoming project with \chandra to observe the coronal soft X-ray emission from members in the central core: at present, only 23 members have been confirmed in the \chandra field; 20 known candidates await RV confirmation/rejection with these spectra.


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 >   2012A-0315

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