[P-PS01] Outer Solar System Exploration Today, and Tomorrow

[PPS01-04] Surface chemistry of the icy Galilean satellites: Observations, laboratory perspectives, and future directions

★Invited Papers

*Samantha K. Trumbo¹ (1.Cornell Center for Astrophysics and Planetary Science, Cornell University, Ithaca, New York, USA)

キーワード：Europa, Galilean satellites, surface composition, spectroscopy

Jupiter's icy Galilean moons—Europa, Ganymede, and Callisto—may host internal oceans of liquid water, making them exciting targets for exploring the potential for habitability elsewhere in the solar system. Evidence for an extant ocean is particularly compelling in the case of Europa, which also features a geologically young surface marred by tectonic fractures, extensional bands, and chaotic terrain likely reflecting exchange with the subsurface. Indeed, for Europa and perhaps the other satellites, the surface chemistry provides our best window into the subsurface composition. However, correct interpretation of surface constituents requires understanding the effects of continuous radiolytic processing by Jovian magnetospheric particles and of long-term exposure to the space environment. Combining observational strategies aimed at disentangling endogenic and exogenic influences and laboratory studies of candidate materials exposed to icy-satellite conditions is key to building a comprehensive understanding of the surface chemistry of these worlds and how they change over time. Focusing primarily on Europa, we review past spectroscopic observations of the surface chemistry, present results of recent observations with the Hubble Space Telescope [1, 2], and discuss complementary laboratory experiments [3, 4]. We also discuss extensions to other icy satellites and remaining questions for future Earth-based and spacecraft investigations.

References:
[1] Trumbo, S. K., Brown, M. E., & Hand, K. P. 2019, SciA, 5, aaw7123
[2] Trumbo, S. K., Becker, T. M., Brown, M. E., Denman, W. T. P., Molyneux, P, A. Hendrix, K.D. Retherford, L. Roth, & J. Alday. 2022, PSJ, 3, 27
[3] Brown, M. E., Denman, W. T. P., & Trumbo, S. K. 2022, PSJ, 3, 28
[4] Denman, W. T. P., Trumbo, S. K., & Brown, M. E. 2022, PSJ, 3, 26