NOAO >   Observing Info >   Approved Programs >   2010A-0394

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Proposal Information for 2010A-0394


PI: Jaehyon Rhee (Jay), Purdue University, jrhee@physics.purdue.edu
Address: Department of Physics, 525 Northwestern Avenue, West Lafayette, IN 47907-2036, U.S.A.

CoI: Michael Fink, Purdue University

Title: Search for r-Process Enhanced Very Metal-Poor Stars

Abstract: We propose to carry out a high-resolution spectroscopy program for very metal-poor (VMP) red-giant stars with [Fe/H] \le -2.5 in the halo and thick disk of the Galaxy. Thanks to previous medium-resolution spectroscopy using NOAO observing facilities, the ongoing PUMPSS (Purdue Ultra Metal-Poor Star Survey) program has so far been able to \emphnewly discover more than 200 VMP red-giant stars with [Fe/H] \le - 2.5 and 12.0 \le B \le 15.5 over a range of sky coverage (including the regions not covered by ongoing extensive surveys for VMP stars). Using the medium-resolution spectroscopic data, r-process enhanced ([r/Fe] > +1.0) red-giant candidates have been chosen. In this semester, we pursue to obtain high-resolution spectra of some 25 candidate r-process enhanced red-giant stars with \emphconfirmed [Fe/H] \le -2.5 and B \le 13.0 using the KPNO 4 m echelle spectrograph. With these data, we seek to discover additional r- process enhanced VMP red-giant stars with detectable Th and U which may allow cosmo-chronometric age determinations. Comprehensive chemical abundance analysis for statistically significant samples of the old and most metal-poor stars placed in various directions and distances will allow us to understand astrophysical times and sites for chemical element production (particularly for the r-process nucleosynthesis) and the formation and structure of the Galaxy.


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 >   2010A-0394

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