A star and its surrounding planets are born from the same molecular cloud, meaning they share a common origin. However, compositional deviations of (particularly rocky) planets from stars are commonplace, and may occur by gas-dust fractionation in the protoplanetary disk and/or over the course of their subsequent dynamical evolution. Using our Solar System as an example, the Earth and the other terrestrial planets are known to be depleted with respect to the Sun in atmosphere-forming elements (H, C, N and O). This depletion also extends, to a lesser degree, to rock-forming elements such as Mg and Si. Observations of polluted white dwarf atmospheres suggest that such a volatile depletion process – i.e. devolatilization – may also take place in rocky exoplanetary materials. However, the mechanisms that lead to devolatilization are yet to be fully understood and are not considered in most (if not all) existing planet formation models.
This session welcomes submissions focusing on either nebular (e.g. dust formation, condensation, and evaporation/sublimation) or post-nebular (e.g. energetic accretion and impacts, hydrodynamic escape, and photoevaporation) processes that may lead to devolatilization in rocky (exo-)planets. Submissions about planet formation models that consider any devolatilization processes are particularly encouraged. Observations and simulations of polluted white dwarf atmospheres and of the properties of rocky exoplanets, for example by reflection/emission spectroscopy, are also invited.
We hope to develop synergies between cosmochemistry, astrochemistry, planet formation dynamics, and exoplanet observations for developing quantitative predictions for the elemental composition of rocky exoplanets. Such information is crucial, together with the current exoplanet observables (i.e. mass, radius and orbital properties), to constrain rocky exoplanetary interiors, surfaces, and atmospheres. Eventually, these will lead to a new level of predictive statistical understanding of the detailed properties of rocky exoplanets in the solar neighbourhood, guiding the future exoplanet-dedicated missions or mission concepts, such as, PLATO, Ariel, HabEx, LUVOIR, and LIFE.