Spectroscopic Studies of Extremely Metal‐Poor Stars with the Subaru High Dispersion Spectrograph. I. Observational Data

We have obtained high-resolution (R $\simeq$ 50,000 or 90,000), high-quality(S/N $\ga$ 100) spectra of 22 very metal-poor stars ([Fe/H] $\la$ -2.5) withthe High Dispersion Spectrograph fabricated for the 8.2m Subaru Telescope. Thespectra cover the wavelength range from 3500 to 5100 {\AA}; equivalent widthsare measured for isolated lines of numerous elemental species, including the$\alpha$ elements, the iron-peak elements, and the light and heavyneutron-capture elements. Errors in the measurements and comparisons withprevious studies are discussed. These data will be used to perform detailedabundance analyses in the following papers of this series. Radial velocitiesare also reported, and are compared with previous studies. At least onemoderately r-process-enhanced metal-poor star, HD 186478, exhibits evidence ofa small-amplitude radial velocity variation, confirming the binary status notedpreviously. During the course of this initial program, we have discovered a newmoderately r-process-enhanced, very metal-poor star, CS 30306-132 ([Fe/H] $=-2.4$; [Eu/Fe] $= +0.85$), which is discussed in detail in the companion paper.Comment: 31 pages, 17 Postscript figures, accepted for publication in ApJ