September 28, 2023

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Speaker: Lia Marta Bernabò, PhD student, German Aerospace Center (DLR) Institute of Planetary Research

Host: Bill Cochran

Title: A radial velocity analysis technique to determine planetary interiors

Abstract: Exoplanets identified with both transits and radial velocities are characterized by their mass and radius, providing an estimate of the mean density and giving a hint on the class of planet (e.g. distinguish a gas giant from a rocky planet). However, the mean density alone cannot uniquely constrain the planetary composition and its interior structure.

The internal structure of exoplanets can be better constrained with the help of a third measurable parameter beyond mass and radius: the second-degree fluid Love number k2. I will illustrate a method to analyze the radial velocity curve in the presence of periastron precession caused by general relativity and tidal interaction between the star and the planet. I will show how it can be linked to the Love number k2 and give a clue on the planetary interior and how we applied such a method to a first case study.

Biography: Lia Marta Bernabò is a third-year PhD student at the German Aerospace Center (DLR) in Berlin, Germany. She applies the theory of tidal interactions on stellar radial velocities data to understand how the planetary orbits evolve with time and link it to the interior structure of the planet itself.

She earned her BSc in Physics in Florence and her MSc in Astronomy in Padua, Italy, where she focused her work on protoplanetary disc evolution and the initial stages of planetary formation.

She is visiting The University of Texas at Austin until March as part of the European exchange program EXOWORLD.