Oliver Herbort - From Atmospheres to Surfaces: Using atmospheric compositions to constrain surfaces of rocky exoplanets How can the atmospheric composition of a rocky exoplanet be used to constrain the the surface composition and conditions of rocky exoplanets?With the current and upcoming generations of space and ground based instruments the characterisation of rocky planets is challenging, but possible. This will open a new window to the understanding of the diversity of rocky exoplanets throughout our galaxy. In general, the diversity of rocky exoplanets is expected to be much more diverse than what we see in our solar system, differing in planetary interiors, surface conditions, and atmospheric compositions. While all of these are connected through geological processes, direct observations are challenging even with current and upcoming ground and space based instruments, showing the importance of models combining planetary atmospheres, surfaces, and interiors. Such models are fundamentally interdisciplinary as they bridge geosciences and astrophysics with further implications to astrobiology. During this talk, I will present our modelling approach for rocky exoplanet atmospheres and focus on some key results. The bottom-to-top surface-atmosphere model is based on a crust-atmosphere interaction layer, which is the starting point of the 1D atmospheric model, which includes the effects of element depletion due to cloud formation. The atmospheric and cloud composition are therefore a result of the surface composition and the pressure-temperature structure. Modelling the variety of different gas-phase compositions reveals the existence of three distinct atmospheric types (H2 rich, O2 rich, or the coexistence of CH4 and CO2), defined by their atmospheric composition. In addition to these distinct atmospheric types, the presence of some cloud condensates provides constraints on the planetary surface temperature and pressure. Furthermore, the composition of the planetary surface mineralogy in contact with the atmosphere provides distinct transitions linked to the atmospheric types. Investigations of various elemental compositions based on different rock compositions reveal links of surface minerals to the atmospheric types. In particular, the sulphur bearing minerals of FeS, FeS2, and CaSO4 as well as the iron oxidisation state can be constrained. Furthermore, the sulphur cloud condensates of H2S and H2SO4 only form for planets with high surface pressures and temperatures. This work shows that in principle, spectroscopic investigations of rocky exoplanet atmospheres can constrain the atmospheric composition to a specific atmospheric type and therefore put some constraints on the expected surface mineralogy. Tags ECPS Colloquium Mar 31 2026 16.00 - 17.00 Oliver Herbort - From Atmospheres to Surfaces: Using atmospheric compositions to constrain surfaces of rocky exoplanets The ECPS Colloquium Series is a regular forum for the planetary science community at the University of Edinburgh to come together, hear about new research, and exchange ideas across disciplines. Featuring talks from invited speakers and members of the Centre, the series is open to all and provides a welcoming space for discussion, networking, and engagement—whether you are already part of ECPS or new to planetary science at Edinburgh. Elm Lecture Theatre, Nucleus Building
Oliver Herbort - From Atmospheres to Surfaces: Using atmospheric compositions to constrain surfaces of rocky exoplanets How can the atmospheric composition of a rocky exoplanet be used to constrain the the surface composition and conditions of rocky exoplanets?With the current and upcoming generations of space and ground based instruments the characterisation of rocky planets is challenging, but possible. This will open a new window to the understanding of the diversity of rocky exoplanets throughout our galaxy. In general, the diversity of rocky exoplanets is expected to be much more diverse than what we see in our solar system, differing in planetary interiors, surface conditions, and atmospheric compositions. While all of these are connected through geological processes, direct observations are challenging even with current and upcoming ground and space based instruments, showing the importance of models combining planetary atmospheres, surfaces, and interiors. Such models are fundamentally interdisciplinary as they bridge geosciences and astrophysics with further implications to astrobiology. During this talk, I will present our modelling approach for rocky exoplanet atmospheres and focus on some key results. The bottom-to-top surface-atmosphere model is based on a crust-atmosphere interaction layer, which is the starting point of the 1D atmospheric model, which includes the effects of element depletion due to cloud formation. The atmospheric and cloud composition are therefore a result of the surface composition and the pressure-temperature structure. Modelling the variety of different gas-phase compositions reveals the existence of three distinct atmospheric types (H2 rich, O2 rich, or the coexistence of CH4 and CO2), defined by their atmospheric composition. In addition to these distinct atmospheric types, the presence of some cloud condensates provides constraints on the planetary surface temperature and pressure. Furthermore, the composition of the planetary surface mineralogy in contact with the atmosphere provides distinct transitions linked to the atmospheric types. Investigations of various elemental compositions based on different rock compositions reveal links of surface minerals to the atmospheric types. In particular, the sulphur bearing minerals of FeS, FeS2, and CaSO4 as well as the iron oxidisation state can be constrained. Furthermore, the sulphur cloud condensates of H2S and H2SO4 only form for planets with high surface pressures and temperatures. This work shows that in principle, spectroscopic investigations of rocky exoplanet atmospheres can constrain the atmospheric composition to a specific atmospheric type and therefore put some constraints on the expected surface mineralogy. Tags ECPS Colloquium Mar 31 2026 16.00 - 17.00 Oliver Herbort - From Atmospheres to Surfaces: Using atmospheric compositions to constrain surfaces of rocky exoplanets The ECPS Colloquium Series is a regular forum for the planetary science community at the University of Edinburgh to come together, hear about new research, and exchange ideas across disciplines. Featuring talks from invited speakers and members of the Centre, the series is open to all and provides a welcoming space for discussion, networking, and engagement—whether you are already part of ECPS or new to planetary science at Edinburgh. Elm Lecture Theatre, Nucleus Building
Mar 31 2026 16.00 - 17.00 Oliver Herbort - From Atmospheres to Surfaces: Using atmospheric compositions to constrain surfaces of rocky exoplanets The ECPS Colloquium Series is a regular forum for the planetary science community at the University of Edinburgh to come together, hear about new research, and exchange ideas across disciplines. Featuring talks from invited speakers and members of the Centre, the series is open to all and provides a welcoming space for discussion, networking, and engagement—whether you are already part of ECPS or new to planetary science at Edinburgh.
