T276 Big Science from Small Worlds

Wednesday, 25 September 2024
1:30 PM - 5:30 PM
213A

REFLECTANCE CHANGES OVER TIME ON SATURNIAN MOONS

Paper number: T276-10
Program: Technical Sessions
Time: 3:55 PM – 4:15 PM

Authors

Abstract

Close observations of the surfaces of icy moons reveals several features that show differences in appearance from images taken at different time. These features may reflect changes due to geologic processes. Some of the moons in the Saturnian system, particularly Titan, Enceladus, and Iapetus, provide evidence for recent surface geologic activity. Titan has visible dune fields, methane lakes, and a hydrologic cycle that all modify its surface. Enceladus has a comparatively young surface, and an active plume at its south pole, which both indicate active or recent processes. Similarly, the two-toned appearance of Iapetus is speculated to reflect an actively changing exterior. The composition of the surface may be evolving as the moon collides with particles from the rest of the system or as the thermal properties of the surface materials change. Other moons show only evidence of past tectonic activity, such as Tethys and Dione, and long histories of impact cratering, such as Rhea. By examining these moons in detail, we can place limits on their surface processes. The impact cratering rate at each of these moons is used to help determine relative surface ages. Similarly, rates of surface deposition of material ejected at Enceladus’s south pole influences our understanding of its history and the mechanics of the plume. By exploring changes on these moons over time, we constrain these rates and expand our understanding of the Saturn system’s surface processes. Saturn and its moons were most recently imaged by the Voyager 1 and 2 missions and the Cassini mission, in 1980-81, and 2004-2017 respectively. The time between images allows us to identify changes across time periods, spectral filters, and missions. We examine both Voyager-to-Cassini comparisons, with a ~35-year time gap, and comparisons within the Cassini mission, with time gaps from months to 12 years between images. Similar studies have used change detection to find new impact craters, detect active volcanism, and study surface processes for the inner solar system. Our study examines multiple Saturnian icy moons and focuses on several features that either exhibit potential evidence of surface processes and changes or demonstrate unusual lighting and albedo changes. We aim to constrain rates of activity on these surfaces through these changes or the lack thereof.

Geological Society of America Abstracts with Programs. Vol. 56, No. 5

doi: 10.1130/abs/2024AM-405155

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