Contribution of Non-Water Ices to Salinity and Electrical Conductivity
in Ocean Worlds
Modeling of the electrical conductivity (EC) of icy moon oceans has
previously assumed that chloride, sulfate, and other ions released from
rock leaching are the main solutes and carriers of electrical
conductivity. Here, we show that accreted volatiles, such as carbon
dioxide and ammonia, can add a significant fraction of solutes in bodies
whose volatile content was in part supplied from cometary materials.
These volatiles can increase the EC of aqueous solutions above 1 S/m.
Our salinity and EC estimates can serve as a basis for planning future
magnetometer investigations at icy moons and dwarf planets. In
particular, oceans expected in some of the Uranian satellites and
Neptune’s satellite Triton could have EC above 3 S/m as a result of
accretion of large abundances of carbon dioxide and ammonia, even if
rock leaching during water-rock separation was limited, and chlorine and
sulfur abundances may be at CI carbonaceous chondritic levels.