Lower Surface Temperature at Bright Ephemeral Feature Site on Titan's North Pole. Issue 7 (6th April 2021)

• Record Type: Journal Article
• Authors: Dhingra, Rajani D.; Jennings, Donald E.; Barnes, Jason W.; Cottini, Valeria
• Is Part Of: Geophysical research letters. Volume 48:Issue 7(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-04-06
• Subjects: CIRS -- fog -- North Pole -- rainfall -- temperature drop -- Titan; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1029/2020GL091708
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: We report a temperature difference in one of the regions on Titan that is, documented as a bright ephemeral feature (BEF). Spectra were recorded by Cassini's Composite Infrared Spectrometer. BEFs are 5 µ m bright areas that appear, disappear, and shift from flyby to flyby at Titan's North Pole observed in Visual and Infrared Mapping Spectrometer (VIMS) data. They are inferred to be broad‐specular reflections caused by a smooth surface on Titan or a near surface fog—both of which indicate that the atmosphere interacted with the surface. We used 24 spectra for "on the BEF" and 51 spectra for "off the BEF" region to determine the temperature difference during the T121 flyby (July 25, 2016). At the 410–560 cm −1 window where surface emissions are perceptible we see a decrease in temperature by 1.2 ± 0.2 K. This decrease in temperature might indicate precipitative cooling after a fresh rainfall on Titan's land/sea surface. Key Points: Visual and Infrared Mapping Spectrometer (VIMS) onboard Cassini identified bright ephemeral feature (BEF) on the North Pole of Titan in the T121 (July 25, 2016) flyby We report a temperature difference of ∼1.2 K in observations from the Cassini's instrument, Composite Infrared Spectrometer at one of the sites of BEF −5 µ m bright areas that appear, disappear, and shift from flyby to flyby at Titan's North Pole observed in VIMS data The discrete surface temperature difference is likely the result of evaporative cooling during precipitation. Such an event is consistent with both wetted surface and fog