Stellar archaeology: A Keck pilot program on extremely metal-poor stars from the Hamburg/ESO Survey. I. Stellar parameters

In this series of two papers, we present a high-dispersion spectroscopic analysis of eight candidate extremely metal-poor stars selected from the Hamburg/ESO Survey ( HES) and of six additional very metal-poor stars. We demonstrate that with suitable vetting using moderate-resolution spectra, the yield of this survey for stars with [Fe/H] less than or equal to -3.0 dex is very high; three out of the eight stars observed thus far at high resolution from the HES are actually that metal-poor, three more have [Fe/H] less than or equal to -2.8 dex, and the remainder are only slightly more metal-rich. In preparation for a large-scale effort to mine the HES database for such stars about to get under way, we lay out in this paper the basic principles we intend to use to determine in a uniform way the stellar parameters T-eff, log g, and reddening.