EXOA9

Unlike the Hertzsprung–Russell diagram for stars, there remains as yet no formal classification for solid exoplanets composed of varying proportions of fluids, rock+metals and ice. Still, as with stars, planetary mass and composition – expressed in geochemical and cosmochemical terms – modulate bulk physical and chemical characteristics that may be detectable by remote observations of exoplanet atmospheres. How can the physical and chemical attributes that control rocky exoplanet interiors (exo-geodynamics) be determined via theory, simulation, observations, phenomenology and experiments? Specific examples include: using galactic chemical evolution to relate the properties and compositions of host stars and their exoplanets; relating chemical geodynamics of rocky planet interiors to system age, stellar class, luminosity and XUV evolution; and, how these properties manifest themselves observationally in the spectra of exoplanetary atmospheres. We invite contributions in the broad new area of geoastronomy that unify principles from astrophysics and the geosciences to advance our understanding of rocky exoplanets in the JWST era and beyond.