Speaker: Jane Birkby (UvA)
Our search for a second Earth has uncovered an incredible diversity in the exoplanet population. Many have no analogue in our solar system, and it is clear that our solar neighbourhood contains but a mere fraction of the possible outcomes of the planet formation process. We do not yet know what causes this diversity, but a key way we can begin to elucidate it is via the characterization of exoplanet atmospheres. From this, we learn how and where the planets gathered materials in their protoplanetary disks, and understand the physical processes that govern them, especially in extreme regimes.
In this colloquium, I will present a relatively new method of study, high-resolution spectroscopy, which is a robust and powerful tool in exoplanet characterization. It uses changes in the Doppler shift of a planet to disentangle its spectrum from the glare of its host star. Its sensitivity to the shape of the planet’s spectral lines gives information about the planet’s atmospheric composition, structure, mass, wind patterns, and rotation. It is highly complementary to other methods devised for HST, Spitzer and JWST. I will demonstrate how this method may be our only avenue forward in the coming decades for characterizing our very nearest temperate rocky worlds, leveraging the ELTs to play a pivotal role in the hunt for biosignatures. These nearby worlds are likely hosted by cool M-dwarf stars, where stellar activity and the prevalence of molecular bands is high. I will briefly discuss some of the mechanisms to circumvent these issues that will affect our ability to perform comparative exoplanetology of rocky worlds.