COMPLEAT

Measuring and modeling the IR absorption spectra of H$_2$O, CH$_4$ and H$_2$ mixed with CO$_2$ is of great importance for planetary sciences. These spectra include a contribution due to the local absorption by the rovibrational lines of each species and a broadband contribution (continua) which are poorly characterized but crucial to understand the radiative budget, the composition of planetary atmospheres and to accurately model the formation, evolution, and present atmospheric state of telluric planets.

The aim of this project is first to better characterize the absorption continua of H$_2$O, H$_2$ and CH$_4$ mixed with CO$_2$, through state-of-the-art laboratory measurements at different temperatures and calculations, and to provide reference datasets to the community studying the atmospheres of telluric planets. The second goal consists in establishing the role of these continua for the atmosphere of ancient Mars and the evolution and observability of magma-ocean planets. These continua will also be used to assess the observability of nearby temperate Earth-size planets with a particular focus on those of the TRAPPIST-1 system.

Project partners:

• LIPHY Laboratoire Interdisciplinaire de Physique (Didier Mondelain)
• LMD Laboratoire de Météorologie Dynamique
• ISMO Institut des Sciences Moléculaires d’Orsay (Olivier Pirali)

This project is funded by the Agence Nationale de la Recherche (ANR-19-CE31-0010).