From atoms to small exoplanets, and back

Ziel

Nature is prolific at creating Earth- to Neptune-sized planets, a discovery that stands as one of the most fundamental in planetary science as such objects do not exist in the Solar System. Despite the many resources devoted to unveiling the nature of these intriguing small exoplanets, including a wealth of observations from cutting-edge telescopes, little is known about them. Advancing that knowledge is at the frontier of today’s exoplanet research and marks a timely step towards comprehending exoplanet diversity. Exo-RARE will push that frontier by investigating atmospheric escape to space from small exoplanets.

The project builds upon two principles widely acknowledged as essential, but that have thus far received unsatisfactory attention that has hindered general understanding of the planets. First, that fully exploiting the information encoded in some atmospheric observables calls for a next generation of models that embrace the atom-scale complexity of atmospheres. Second, that arguments such as an atmosphere’s long-term stability yield insight into small exoplanets in ways that are not possible using other approaches including IR molecular spectroscopy. This insight is urgently needed to overcome current roadblocks in the characterization of small exoplanets.

By leveraging my unique expertise in atmospheric escape and disequilibrium, the project will develop novel diagnostics and break ground in the investigation of small exoplanets’ compositions and demographics. To be effective, it will proceed by addressing various topical problems. This original and ambitious project will set new standards for exoplanet atmosphere models. Public dissemination of the models and the data shortcomings they reveal will spur valuable synergies with the exoplanet observers and atomic-physics theorists/experimentalists whose work is at the core of this project. Looking forward, the project findings will help prioritize known exoplanets for future biosignature searches.