NOAO >   Observing Info >   Approved Programs >   2011A-0085

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Proposal Information for 2011A-0085


PI: Geoffrey Clayton, Louisiana State University, gclayton@fenway.phys.lsu.edu
Address: Dept. of Physics and Astronomy, Baton Rouge, LA 70803, USA

CoI: Tom Geballe, Gemini Observatory - North

Title: Z Umi: A Critical Test of the formation path(s) of R Coronae Borealis Stars

Abstract: We request 0.5 hours of time on NIRI/Gemini North to follow up on one key aspect of our discovery of extreme 18O enrichment in hydrogen-deficient carbon stars and R Coronae Borealis (RCB) stars in the Galaxy (Clayton et al. 2005, 2007). The proposed observation would consist of a high S/N medium resolution GNIRS spectrum of the CO bands in the RCB star, Z UMi to confirm a previous marginal detection of a large abundance of 18O in it. Z UMi may be unique in possessing measurable amounts of both 18O and Li among the RCB stars. If an RCB star is found that has both a high Li abundance and a high 18O abundance, it would force a re-evaluation of the proposed scenarios for the formation of the RCB stars. The proposed Gemini observations will provide a definitive answer to whether an RCB star can have both Li and highly overabundant 18O.


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NOAO >   Observing Info >   Approved Programs >   2011A-0085

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