IRTF Data Archive Program Information

# # Program information file # PROGRAM_ID 2023B003 PROGRAM_TITLE Is CO2 ice concentrated at low latitudes on the classical Uranian moons? PROGRAM_INV1 Richard Cartwright PROGRAM_INV2 David DeColibus PROGRAM_INV3 Will Grundy PROGRAM_INV4 Bryan Holler PROGRAM_INV5 Tom Nordheim PROGRAM_SCICAT major planets / satellites PROGRAM_ABSTRACT_BEG We propose to use the SpeX spectrograph on NASA's Infrared Telescope Facility to investigate whether the CO2 ice detected on the Uranian moons participates in a seasonal sublimation cycle, migrating from their poles to low latitude cold traps. We would collect new SpeX spectra at high sub-observer latitudes [current sub-obs. latitude 63 degrees N], measure CO2 bands in these data, and compare the resulting CO2 band measurements to those made using spectra collected at lower sub-obs. latitudes [< 45 degrees N]. If we find a reduction in CO2 ice band strengths at high sub-observer latitudes on all four moons, this would support seasonal migration in response to subsolar heating. If we do not detect a consistent reduction in CO2 band strengths, this would suggest regional geology on each moon is the primary driver of the distribution of CO2 ice. The SXD mode of SpeX [R ~750, 0.8'' slit] is ideal for the characterization of the three narrow CO2 bands between 1.9 and 2.1 microns [0.004 -- 0.007 microns wide], requiring a minimum R > 518 to detect all of these features. To improve the quality of collected SXD spectra, we will guide using MORIS [0.7-micron dichroic], thereby mitigating slit losses. PROGRAM_ABSTRACT_END