Near-Infrared Spectral Monitoring of Pluto's Ices II: Recent Decline of CO and N${}_2$ Ice Absorptions

Abstract

IRTF/SpeX observations of Pluto's near-infrared reflectance spectrum during 2013 show vibrational absorption features of CO and N${}_2$ ices at 1.58 and 2.15 μm, respectively, that are weaker than had been observed during the preceding decade. To reconcile declining volatile ice absorptions with a lack of decline in Pluto's atmospheric pressure, we suggest these ices could be getting harder to see because of increasing scattering by small CH${}_4$ crystals, rather than because they are disappearing from the observed hemisphere.

10 pages, 1 table, 2 figures

References in corpus (2)

• New Horizons: Anticipated Scientific Investigations at the Pluto System
• Absorption Coefficients of the Methane-Nitrogen Binary Ice System: Implications for Pluto

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• Evaluation of short-term temporal evolution of Pluto's surface composition from 2014-2017 with APO/TripleSpec
• Evidence for longitudinal variability of ethane ice on the surface of Pluto