A modelling study published in Nature Communications suggests that oceans on water-rich exoplanets may be enriched with electrolytes, including salts like sodium chloride. The study proposes that electrolytes can be transported from these planets’ rocky cores, which may have implications for the potential habitability of these ocean worlds.
Water-rich exoplanets and icy moons are ideal environments for biological processes. A rocky core separates the planets from liquid water by a high-pressure ice shell. It has been debated whether the ice shell impedes the transport of electrolytes from the rocky core into the liquid ocean.
Jean-Alexis Hernandez and colleagues investigated how electrolytes could be transported between the ice layer and the ocean on these planets using molecular dynamics simulations and thermodynamic modelling. The researchers discovered that salts like sodium chloride could be incorporated into high pressure ice shells and transported through the ice into the ocean. They argue that this proves high-pressure ice mantles do not act as chemical barriers between rocky cores and liquid water oceans.
Baptiste Journaux writes in an accompanying Comment that the study “offers the most convincing argument yet in resolving the dilemma of large planetary hydrosphere habitability.”