- Poor Stars . Viii . High - Resolution , High - Signal - to - Noise Analysis

High-resolution, high-signal-to-noise (〈S/N〉 = 85) spectra have been obtained for five stars – CD–2417504, CD–38245, CS 22172–002, CS 22885–096, and CS 22949–037 – having [Fe/H] . –3.5 according to previous lower S/N material. LTE model-atmosphere techniques are used to determine [Fe/H] and relative abundances, or their limits, for some 18 elements, and to constrain more tightly the early enrichment history of the Galaxy than is possible based on previous analyses. We compare our results with high-quality higher-abundance literature data for other metal-poor stars and with the canonical Galactic chemical enrichment results of Timmes et al. (1995) and obtain the following basic results: (1) Large supersolar values of [C/Fe] and [N/Fe], not predicted by the canonical models, exist at lowest abundance. For C at least, the result is difficult to attribute to internal mixing effects; (2) We confirm that there is no upward trend in [α/Fe] as a function of [Fe/H], in contradistinction to some reports of the behavior of [O/Fe]; (3) The abundances of aluminum, after correction for non-LTE effects, are in fair accord with theoretical prediction; (4) We confirm earlier results concerning the