P075-03
Geochemistry as a Tool for Magnetic Induction, Gravity, and Seismology in Icy Ocean Worlds

Wednesday, 16 December 2020: 04:08
Virtual
Steve Vance1, Bruce G Bills1, Mark P Panning2,3, Corey Cochrane4, Krista Marie Soderlund5, Tom Nordheim6, J Michael Brown7, Baptiste Journaux8, Marshall John Styczinski9, Carol S Paty10, Saikiran Tharimena11, Mohit Melwani Daswani12, Marc Neveu13, Angela G Marusiak14, Samentha Dumervil15 and Keith Chin16, (1)Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, United States, (2)Univ of FL-Geological Sciences, Gainesville, FL, United States, (3)JPL/NASA/Caltech, Pasadena, CA, United States, (4)Jet Propulsion Laboratory, Pasadena, CA, United States, (5)University of Texas at Austin, Institute for Geophysics, Austin, TX, United States, (6)NASA Jet Propulsion Laboratory, Pasadena, CA, United States, (7)University of Washington Seattle Campus, Seattle, WA, United States, (8)University of Washington, Earth and Space Sciences, Seattle, WA, United States, (9)University of Washington Seattle Campus, Physics, Seattle, WA, United States, (10)University of Oregon, Earth Sciences & Clark Honors College, Eugene, OR, United States, (11)University of Vienna, Vienna, Austria, (12)JPL/NASA/Caltech, Pasadena, United States, (13)Arizona State University, School of Earth & Space Exploration, Tempe, AZ, United States, (14)University of Maryland College Park, Geology, College Park, MD, United States, (15)Howard University, Chemical Engineering, Washington, DC, United States, (16)NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, United States
Recorded Presentation
Abstract:
In icy ocean worlds the hydrosphere is a geophysically significant fraction of the bulk volume. For example, Ganymede’s hydrosphere occupies about 75% of its total volume. Understanding the global geophysical properties of such worlds requires information on the petrology and geochemistry of ices and fluids in detail commensurate to the sensitivity of planned geophysical investigations. Key data are still needed for the Europa Clipper, JUICE, and Dragonfly missions to Europa, Ganymede, and Titan, respectively, which all have planned operations within the next 16 years. Electrical conductivity data to significant pressures are only available for aqueous MgSO4, but NaCl may be a more likely main component of the oceans. Most available data extend only to very low salinity and not to subzero temperatures. Adding to this dearth, ice hydrates are likely to trap significant amounts of salt, but the thermodynamic and seismic properties of such materials have not been studied extensively. We will describe geophysical models for icy ocean worlds that incorporate available thermodynamic data, allowing us to evaluate the radial structures for different assumed compositions and thermal states. By exploring the bounds placed by available and yet-to-be-obtained geophysical data, this forward modeling approach aims to identify which experimental measurements are most needed.
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