NOAO >   Observing Info >   Approved Programs >   2008A-0387

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Proposal Information for 2008A-0387


PI: Kenneth Hinkle, NOAO, hinkle@noao.edu
Address: NGSC, P.O. Box 26732, Tucson, AZ 85726, USA

CoI: David L. Lambert, University of Texas at Austin
CoI: Richard Joyce, NOAO

Title: Mass Loss and Abundances in the Final Flash

Abstract: CO first overtone lines will be observed in FG Sge to determine the C and O isotopic ratios. FG Sge, considered a key to understanding post- AGB evolution when it was discovered, is unlike any other post-AGB object and increasingly a theoretical problem. The isotope ratios will help determine which of several possible evolutionary paths this star is following. We will also observe the CO fundamental and He I 10830 A in FG Sge and other final helium shell flash stars. The CO column density and He I 10830 Aline profiles will be used to determine the mass loss rates. The CO line profiles allow the geometry of the circumstellar region to be modeled. With the exception of FG Sge the final flash stars have evolved into a hot white dwarf with an obscuring dust disk. FG Sge has been evolving at a rate more than 10 times slower. We would like to look for indications that a disk and a dust condensation shock zone marked by 10830 Aemission are forming around FG Sge.


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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