Cyril Gapp

Cyril Gapp   (Germany)

gapp @

Observational characterization of transiting exoplanets’ atmospheres

Ever since the first confirmed discovery of planets outside of the Solar System in 1992, the development of various techniques for the detection of exoplanets has led to the discovery of thousands of planets that revolutionized our understanding of the diversity of planets in the Universe. With the vast number of exoplanets known today, several fundamental questions have arisen: How do planets form in vastly different environments? Which planets have atmospheres? What implications do the planets’ different environments have for their composition? Is there life outside of the Solar System? To address these and other questions, one class of exoplanets stands out as one of the most promising ones to characterize in detail: Transiting exoplanets that pass in front of their host star as viewed from Earth during their orbits. These planets present a unique opportunity to study their atmospheres, since a portion of the light emitted by the host star transmits through the planet’s atmosphere while the planet passes in front of its host star (the transit), leaving an imprint of the absorbing molecules in the planet’s atmosphere on the star’s radiation one can observe. Additionally, when the planet disappears behind its host star (the eclipse), one can measure the total flux received from the planet by measuring the drop of total flux received by the star and planet together, effectively differentiating stellar and planetary radiation.
By observing transiting exoplanets with cutting-edge observatories such as the Hubble (HST) and James Webb Space Telescopes (JWST), we are now able to study the chemical composition, thermal structure and dynamics of exoplanets’ atmospheres. In my research, I use HST and JWST to target planets from sizes smaller than Neptune, but greater than Earth, up to giant planets larger than Jupiter to constrain their formation, evolution and current climate.

Supervisor:    Tom Evans   (MPIA)

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