Austrian Early Career Conference 2024

Contribution:
Poster

Authors:
Nandini Jain

Affiliations:
University of Potsdam

Title:
Investigating the exoplanetary atmosphere of HAT-P-30b

Abstract:
Characterizing the atmospheres of exoplanets is essential in order to understand their nature and provide clues about their formation and evolution. To this aim, transiting exoplanets are crucial in atmospheric studies as they allow very precise characterisation of the atmosphere due to the known planetary properties (planetary mass and radius). Transmission spectroscopy is a technique for the detection and characterisation of exoplanetary atmospheres. This method compares spectra taken inside and outside of transits to extract the planetary signal. Low-resolution transmission spectroscopy uses an instrument with low resolving power (R=50,000). The latter enables us to resolve the moving planetary motion during the transit. In addition, this technique allows to resolve planetary features from which information like planetary rotation, winds and chemical composition can be derived.
This project aimed at using archival data from FORS2 to study the atmosphere of HAT-P-30b, a hot Jupiter with a very small density and large scale height – and thus an ideal target for transmission spectroscopy as the expected signal is very high. In the ESO archive there were 1556 FORS2 spectra from two transit nights using the 600B and 600RI grisms. We analyzed the FORS2 data, following the method of sedaghati2017detection and nikolov2018absolute, to obtain the low-resolution transmission spectrum and identify the presence of strong absorbers and/or Rayleigh scattering. The calculated equilibrium temperature of HAT-P-30b puts this planet just between two sub-classes of hot Jupiters with different planetary chemistry and composition.
The (non-)detection of certain absorbers in the atmosphere provides strong constraints about temperature and detect eventual temperature inversion layers. This was done using theoretical models from the PetitRADTRANS.