Influence of different host stars upon the atmospheres of planets at the boundary of rocky and gas planets

• Applicant: Dr. Mareike Godolt
• Subject Area: Astrophysics and Astronomy
• Term: from 2017 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 329164484

A major issue in exoplanet science is to determine the nature of planets at the boundary of rocky and gaseous planets. To achieve this, the key processes which determine their atmospheres and their spectral appearance need to be understood. The atmospheres of these planets are accessible by current and near future instruments if they orbit nearby, bright stars. These planets orbit different types of stars and the origin of their atmospheres may be diverse, formed e.g. by accretion from the stellar nebula, sublimation of ices and/or outgassing from the interior.This project therefore aims at understanding the influence of different host stars and atmospheric origins upon the atmospheres of planets in the sub-Neptunian mass-radius regime and their spectral appearance. It will determine whether and which spectral signatures can be used to distinguish between mainly rocky and gaseous planets.To study the impact of different stars a coupled atmosphere model is needed hat accounts for the influence of different stellar irradiation upon the atmospheric temperatures and composition. A new coupled atmosphere model will be developed which calculates the atmospheric temperatures via radiative and convective energy transport, utilizing a line-by-line radiative transfer model. This radiative-convective model will be coupled to equilibrium and non-equilibrium chemistry models to consider the impact of the temperature structure and the stellar irradiation upon the atmospheric chemical composition. From the resulting atmospheric profiles the spectral appearance of these planets and the detectability of spectral features with current and future instruments will be determined.

• DFG Programme: Research Grants