Presentation #117.02 in the session Laboratory Astrophysics (LAD) Division Meeting: The Salty Solar System I.
The last NRC planetary science decadal survey, Vision & Voyages for Planetary Science in the Decade 2013-2022, states that “because of this ocean’s potential suitability for life, Europa is one of the most important targets in all of planetary science.” The aspiration to better understand and characterize the habitability of Europa’s ocean, at least in part, is a question of understanding its composition. Although new technologies are being considered and developed to one day allow access to the ocean with the scientific payload of a robotic spacecraft, direct ocean sampling is many years away. Until such a time as direct sampling becomes a reality, we will need to rely heavily on surface properties to deduce the composition of the underlying ocean. The ability to make such inferences not only assumes that salt minerals on the surface are the result of the emplacement of frozen ocean brines, but will rely on our understanding of the chemistry that governs the freezing and mineral formation during emplacement. Over the last few years, our group at JPL has been investigating this chemistry in an attempt to create meaningful linkages between the surface and ocean chemistries. Geochemical modeling suggests that Na+, Mg2+, Cl-, and SO42- are among the ions expected to be in abundance within the ocean. As such, our studies have focused on the freezing of brines containing these species as reprentative putative Europan ocean fluids. This talk will review this body of work.