Transmission spectroscopy analyses of Jovian planets with Hubble Space Telescope

Abstract

Studying the chemical compositions of exoplanetary atmospheres provides valuable information about the conditions and characteristics of those atmospheres, which could help search for signs of extraterrestrial life. To date, over 3,000 exoplanets have been discovered using the transit method. The transmission spectroscopy technique, which studies exoplanetary atmospheres during their transits, is widely used to study the atmosphere of transiting exoplanets. Wide Field Camera 3 (WFC3), an instrument on the Hubble Space Telescope (HST), use the transmission spectroscopy technique by observing the spectrum of light curves of transiting exoplanets in optical and infrared wavelengths, which could reveal some molecular absorption in the exoplanetary atmosphere. In this work, we study the atmospheres of 20 transiting exoplanets that are Jovian planets. Light curves of these exoplanets observed by the WFC3 are used to analyze their physical properties using the Iraclis package and transit depth using the TransitFit package, a python exoplanetary fitting package based on nested sampling algorithms. Our physical parameters from TransitFit are approximately the same as those in previous literature. Finally, TauREx 3, a fully Bayesian spectral retrieval code, analyzes the transit depth per wavelength channel and reveals atmospheric compositions of these exoplanetary atmospheres. One notable finding from our analysis is the detection of 5−3+8% H2O abundance in the atmosphere of WASP-63 b.