Structure and evolution models for Uranus, Neptune, and extrasolar planets with observed Love number k2

• Applicant: Dr. Nicola Tosi, since 7/2022
• Subject Area: Astrophysics and Astronomy ; Mineralogy, Petrology and Geochemistry
• Term: from 2017 to 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 280637173

Observational exoplanet surveys suggest that planets in the size range of 1.7 to 4.0 Earth radii are the most abundant planets in the Solar neighborhood. Since the ice giants Uranus and Neptune are our solar system representatives for this class of planets, we label them collectively Neptune-like. The proposed work aims to understand the internal structure and evolution of Neptune-like planets. Parameters of interest in this regard are the luminosity of Uranus and Neptune and the Love number k2 of extrasolar planets. We will investigate how internal redistribution of elements of the HCNO complex due to demixing or partitioning affects the luminosity of the cool ice giants Uranus and Neptune. These planets are not homogeneous, perhaps due to such redistribution or because of the formation process. We will investigate if stable stratification with conductive heat transport can occur as a result of the significant conductivity of water in the deep interior and across the compositional gradient zones as indicated by the gravity field. For that purpose we rely on predictions on the structural properties and equation of state data from experiments and simulations of water, ammonia, methane, hydrogen, and their mixtures where available, e.g. from SP3 and SP9. Furthermore, we will develop structure models of extrasolar planets with measured Love number k2 from SP6. While the tidal potential field deformation (k2) is accessible by measurements of radial velocity (RV) and transit timing (TT) variations, the shape deformation (h2) is accessible by transit light curve (TLC) analysis. We will investigate if the relation h2=1+k2 as known in the limit of spherical objects is still applicable if the planet is exposed to strong tidal forcing, as will be the case for those exoplanets for which k2 and h2 can be measured.

• DFG Programme: Research Units
• Subproject of: FOR 2440: Matter Under Planetary Interior Conditions - High-Pressure, Planetary and Plasma Physics
• Co-Investigators: Professorin Dr. Doris Breuer; Dr. Martin French
• Ehemalige Antragstellerinnen / Ehemalige Antragsteller: Dr. Nadine Nettelmann, from 7/2021 until 7/2022; Professor Dr. Ronald Redmer, from 7/2020 until 6/2021