We propose high-resolution near-infrared spectroscopic observations of comet C/2021 S3 (PanSTARRS), which is classified as a "dynamically new comet" that is coming from the Oort Cloud directly into the inner solar system for the first time. Members of this group are considered the most pristine icy small bodies in the solar system, as they are the least affected by solar heating. To obtain information contained within ices in the proto-planetary disk of the Sun, observations of dynamically new comets near perihelion passage are essential. Although the surface layer of a cometary nucleus stored in the Oort Cloud for 4.6 Gyrs may be damaged down to a few meters in depth, most of such a damaged layer is expected to be lost by sublimation as it reaches perihelion for the first time. Thus, we propose obtain the original chemistry of cometary ice by observing this dynamically new comet about one month after perihelion. We propose to measure the chemical composition of a suite of cometary molecules (C2H6, C2H2, H2O, CH3OH, HCN, NH3, as well as other minor species, together with H2O) using NIRSPEC at Keck II.
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