HydroSphere: an open source code to model the structure and thermodynamic equilibria of water dominated planetary shells.

Abstract:

Water thermodynamics is complex, especially at high pressures where compressed liquid water behaves anomalously and a multitude of high pressure ice polymorphs exist. Previous models of planetary hydrospheres have relied on simplified parameterizations of thermodynamic properties such as density, phase transitions, and heat capacity. This approach results in fundamental thermodynamic incompatibilities that have often been disregarded due to insufficient constraints. Recent work now enables self-consistent, high-accuracy thermodynamic calculations of all water phases based on derivations of the Gibbs energy of each water phase using the open-source “SeaFreeze” code. Based on this advanced thermodynamic framework, HydroSphere is an interactive framework to compute one dimensional structures of water-dominated shells of planets and moons that runs on Jupyter Notebook with a Python 3.0+ core. HydroSphere can compute the structure of water-rich planetary bodies from small icy moons like enceladus to Super-Earth ocean exoplanets based on six inputs (surface pressure and temperature, mass of water, radius and the density of the rocky core, bottom heat flux). Furthermore, it calculates all associated thermodynamic and elastic properties throughout the water column (e.g. temperature, pressure, heat capacity, bulk modulus, heat flux, shear modulus, pressure and shear seismic wave velocities). It provides the planetary science and exoplanet communities with an accurate thermodynamic framework to explore the effect of the structure on tidal dissipation, seismology and potential habitability of water-rich worlds.