Date of Award

6-2022

Document Type

Open Access

Degree Name

Bachelor of Science

Department

Physics and Astronomy

First Advisor

Heather Watson

Keywords

Europa, saltwater, thermodynamics, modeling, experiment, planetary science, physics, Jupiter, ocean, astrobiology

Abstract

We explore the properties of the hydrosphere on Europa involving both a modeling technique and experimental methods. We perform a computational analysis of the thermodynamic properties for an ideal, pure-water Europan ice shell using a Python programming framework called SeaFreeze. We create four models assuming surface temperatures of either 50 K or 140 K and ice shell thicknesses of either 3 km or 30 km. We observe mostly linear trends for the density and seismic wave velocities with respect to depth and find that surface temperature has the greatest effect on the models. Simultaneously, we experimentally investigate the phase diagram of different saltwater concentrations in an attempt to further constrain the ice shell properties. We determine the freezing temperatures of 5%, 10%, and 20% by-weight NaCl-water solutions under constant pressures from 0 MPa to 70 MPa. We find increasing the salt concentration, the pressure, or both decreases the freezing point temperature with a depression at our most extreme conditions of about -20 °C from that of pure water at zero pressure. Based on our experimental results, we expect that adding NaCl to the pure-water models would lower their ice-water boundary temperatures. Areas of future development include continuing to explore the phase diagrams of different saltwater concentrations, including MgSO4, KCl, and varying combinations of all three salts, extending the pure-water SeaFreeze models to analyze Europa’s subsurface ocean layer, implementing various new techniques to make our experiments more precise, and finally applying our results to the other icy moons, such as Ganymede or Callisto.

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Rights Statement

In Copyright - Educational Use Permitted.