Chemical Abundance Patterns of Extremely Metal-Poor Stars with [Fe/H]≲ -3.5

We present preliminary results on the chemical abundance patterns of extremely metal-poor stars obtained during an ongoing observing program with Subaru/HDS. High-resolution, high signal-to-noise spectra have been obtained for 14 stars with [Fe/H]≲ -3. Five of them exhibit clear overabundances of carbon, a remarkable characteristic found only in the most metal-poor range. One of the carbon-rich stars, HE 1327-2326, has [Fe/H]_NLTE=-5.4, the lowest Fe abundance known. No stars with {-}5 {[Fe/H] { have yet been found in our program, suggesting that quite different enrichment processes were responsible for stars with [Fe/H] { and [Fe/H] {>} {-}4. While neutron-capture elements are deficient in most of our stars, one star (BS 16550-087) exhibits large enhancements of its light neutron-capture elements (Sr, Y and Zr), providing a strong constraint on models for the production of such elements in the very early Galaxy.