The Case for High-Resolution Infrared Spectroscopy with the Habitable Worlds Observatory

Abstract: A high-resolution near-IR spectroscopy capability on the Habitable Worlds Observatory (HWO) could strongly and efficiently advance many of the mission's goals. The technical barriers that made such a capability unfeasible on previous missions have largely been eliminated. Many HWO science case development documents require high spectral resolution in the IR and others would benefit significantly from it. High resolution improves the detectability of weak, unresolved features, aids identification of those features and provides additional information about radial velocity and line shape. It will be significantly easier to remove contaminating stellar features from high-resolution data. Silicon diffractive optics, immersion gratings and grisms, together with the new generation of low-noise, low dark-current avalanche photodiode arrays, make it possible to design a very compact high-resolution spectrograph that can cover the entire 1.1-2.0 micron band in a single exposure that would realize all of these advantages. We outline here the case for such an instrument and the technology development pathway needed to mature it in preparation for the HWO mission.