Stellar Archaeology: A Keck Pilot Program on Extremely Metal-poor Stars from the Hamburg/ESO Survey. I. Stellar Parameters

Abstract

In this series of two papers we present a high dispersion spectroscopic analysis of 8 candidate extremely metal poor stars selected from the Hamburg/ESO Survey and of 6 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] $le -3.0$ 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] $le -2.8$ dex, and the remainder are only slightly more metal rich. In preparation for a large scale effort to mine the Hamburg/ESO Survey database for such stars about to get underway, we lay out in this paper the basic principles we intend to use to determine in a uniform way the stellar parameters Teff, surface grav, and reddening.Comment: The first in a set of two papers, accepted for publication by the A