Abstract:
The technique of transmission spectroscopy --- the variation of the planetary radius with wavelength due to opacity sources in the planet’s terminator region --- has been to date one of the most successful in the characterization of exoplanet atmospheres, providing key insights into the composition and structure of these distant worlds. One underlying assumption of the technique, however, is that the variations are the same in the entire terminator region. In reality, the morning and evening regions might have distinct temperature, pressure and thus compositional profiles due to the inherent 3-D nature of the planet which would, in turn, give rise to different spectra on each side of it. Constraining those might give precious insights into circulation patterns and compositional stratification which might prove to be fundamental for our understanding of not only the weather patterns in the planets under study, but also of planetary formation signatures which might only be possible to extract once these features are well understood. Motivated by this physical picture, in this talk I will present our theoretical and observational efforts towards the detection of these patterns in transmission spectra. In particular, I will present a new, open-source semi-analytical framework with which this information can be extracted directly from transit lightcurves, which opens an exciting window for researchers into the characterization of exoplanet atmospheres with current and upcoming high-precision (spectro)photometric facilities. I will present our current efforts to detect this effect exploiting the exquisite photometric precision of TESS, and future endeavors of detecting it with upcoming observatories such as JWST.