NOAO >   Observing Info >   Approved Programs >   2013A-0309

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Proposal Information for 2013A-0309


PI: Geoffrey Clayton, Louisiana State University, gclayton@fenway.phys.lsu.edu
Address: Physics Department, Nicholson Hall, Baton Rouge, Louisiana 70803, United States

CoI: Wanshu Zhang, Louisiana State University
CoI: Patrick Tisserand, Mount Stromlo Observatory
CoI: Doug Welch, McMaster University
CoI: Tom Geballe, Gemini Observatory - North

Title: What is the true Population of R Coronae Borealis Stars in the Galaxy?

Abstract: The R Coronae Borealis (RCB) stars are rare hydrogen-deficient, carbon-rich supergiants. Two evolutionary scenarios have been suggested, a double degenerate merger of two white dwarfs (WDs), or a final helium shell flash in a PN central star. The evidence pointing toward a WD merger or a FF origin for RCB stars is contradictory. The population of RCB stars in the Galaxy may be consistent with the number of He/CO WD mergers. If so this would be an exciting result since RCB stars may be low-mass analogs of Type Ia SNe. But only 75 of the predicted 3000 RCB stars in the Galaxy have been discovered. Using the recent release of the WISE All-Sky Catalog, a series of IR color-color cuts have produced a sample of candidates that may yield over 200 new RCB star identifications. A pilot project to get spectra of the brighter candidates has yielded more RCB stars than predicted. We are proposing for time on the SOAR 4m with the Goodman spectrograph to obtain spectra of the fainter candidate stars available in the southern hemisphere to investigate the true population of RCB stars.


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 >   2013A-0309

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