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From high resolution (R = 45,000), high signal-to-noise (S/N > 400) spectragathered with the Immersion Grating Infrared Spectrograph (IGRINS) in the H andK photometric bands, we have derived elemental abundances of two bright,well-known metal-poor halo stars: the red giant HD 122563 and the subgiant HD140283. Since these stars have metallicities approaching [Fe/H] = -3, theirabsorption features are generally very weak. Neutral-species lines of Mg, Si, Sand Ca are detectable, as well as those of the light odd-Z elements Na and Al.The derived IR-based abundances agree with those obtained fromoptical-wavelength spectra. For Mg and Si the abundances from the infraredtransitions are improvements to those derived from shorter wavelength data.Many useful OH and CO lines can be detected in the IGRINS HD 122563 spectrum,from which derived O and C abundances are consistent to those obtained from thetraditional [O I] and CH features. IGRINS high resolutions H- and K-bandspectroscopy offers promising ways to determine more reliable abundances foradditional metal-poor stars whose optical features are either not detectable,or too weak, or are based on lines with analytical difficulties.

The Chemical Compositions of Very Metal-Poor Stars HD 122563 and HD 140283; A View From the Infrared