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Spitzer IRS Observations of Titan as a Precursor to JWST MIRI Observations Published: 5/22/2023 8:06:27 PM Updated: 5/22/2023 8:06:27 PM

Paper abstract: In this work we present, for the first time, infrared spectra of Titan from the Spitzer Space Telescope (2004-2009). The data are from both the short wavelength-low resolution (SL, 5.13-14.29\mathrm{\mu m}, R~60-127) and short wavelength-high resolution channels (SH, 9.89 - 19.51\mathrm{\mu m}, R~600) showing the emissions of CH_{4}, C_{2}H_{2}, C_{2}H_{4}, C_{2}H_{6}, C_{3}H_{4}, C_{3}H_{6}, C_{3}H_{8}, C_{4}H_{2}, HCN, HC_{3}N, and CO_{2}. We compare the results obtained for Titan from Spitzer to those of the Cassini Composite Infrared Spectrometer (CIRS) for the same time period, focusing on the 16.35-19.35\mathrm{\mu m} wavelength range observed by the SH channel but impacted by higher noise levels in CIRS observations. We use the SH data to provide estimated haze extinction cross-sections for the 16.67-17.54\mathrm{\mu m} range that are missing in previous studies. We conclude by identifying spectral features in the 16.35-19.35\mathrm{\mu m} wavelength range, including two prominent emission features at 16.39 and 17.35\mathrm{\mu m}, that could be analyzed further through upcoming James Webb Space Telescope Cycle 1 observations with the Mid-Infrared Instrument (5.0-28.3\mathrm{\mu m}, R~1500-3500). We also highlight gaps in current spectroscopic knowledge of molecular bands, including candidate trace species such as C_{60} and detected trace species such as C_{3}H_{6}, that could be addressed by theoretical and laboratory study.