NOAO >   Observing Info >   Approved Programs >   2004A-0466

# Proposal Information for 2004A-0466

PI: Jaehyon Rhee, Caltech, rhee@caltech.edu
Address: Space Astrophysics Laboratory, 1200 E. California Blvd., MC 405-47, Pasadena, CA 91125

CoI: Inese Ivans, Caltech
CoI: Andrew McWilliam, OCIW

Title: Chemical Compositions of Newly Discovered Extremely Metal-Poor Giants from the HK-II Survey

Abstract: We propose to initiate a \it new high-resolution spectroscopy program for extremely metal-poor (EMP) 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 HK- II survey has been able to newly discover some 100 [Fe/H] \le -2.5 giants with 11 \le B \le 16, over 7000 deg^2 (one-sixth of the entire sky). Comprehensive chemical abundance analyses for the stars placed at various directions and distances will allow us to understand early history of the Galactic chemical evolution and place a strong constraint on lower limits on the age of the Universe by age dating of individual r-process enhanced EMP giant stars. The results from this effort will enable us to have refined'' metallicity distribution function of [Fe/H] \le -2.5 populations and, combined with proper motions from astrometric surveys (e.g., UCAC2), will provide full space motions of the extremely old stars to uncover the dynamical history of the early 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 >   2004A-0466