Astro-Seminar: Nidhi Bangera - Decoding Exoplanet Atmospheres through Disequilibrium Chemistry

Wednesday, 21 October 2026 at 13:30

Astrophysics seminar as part of the seminar series occurring every Wednesday at 13:30 during term time. Organised by Till Kaeufer, Vito Squicciarini, Nils de Vries. Contact: Astro-Seminar-Organiser@exeter.ac.uk

Event details

Abstract:

Molecular detections in exoplanet atmospheres provide valuable insights into their physical conditions, chemical processes, and formation histories. However, interpreting these observations is complicated by the interplay between chemical reactions, transport between different atmospheric layers, and photochemistry. These processes can drive atmospheres away from thermochemical equilibrium, creating molecular signatures that do not always uniquely trace underlying atmospheric properties.

In this talk, I will explore how disequilibrium chemistry shapes the observable atmosphere of gas-giant exoplanets. First, I will present a case study of WASP-69b, investigating how vertical mixing and elemental composition influence molecular abundances and the interpretation of high-resolution observations. Second, I will extend the investigation to three-dimensional atmospheric structures, examining the spatial distributions of methane and sulfur dioxide and their implications for transmission spectroscopy. Finally, I will present a population study exploring how stellar irradiation and vertical mixing influence chemical asymmetries between the morning and evening terminators of gas giants.

Together, these studies show how atmospheric structure and disequilibrium processes complicate the interpretation of molecular signatures and identify the conditions under which these effects matter most for understanding exoplanet atmospheres.

Organiser

Astrophysics

Location

Fourth floor interaction area, Physics Building, Streatham Campus