1370

William Pluriel

The impact of the 3D structure of exo-atmospheres on transmission spectra

Transmission spectroscopy provides us with information on the atmospheric properties at the limb, which is often intuitively assumed to be a narrow annulus around the planet. However, exoplanetary atmospheres are complex 3D objects and more and more study show that the region probed in transmission actually extends significantly toward the day and night sides of the planet. It is so not so simple to extract information of the transmission spectra with the actual retrieval tools, which assume a single 1D forward model, thus assuming a uniform limb or a linear combination of 1D models to account for heterogeneities between different regions of the limb (e.g. east vs. west). We will present here a work where we study the impact of the 3D structure of hot exo-atmospheres on the retrieval analysis. We first did this analysis in low resolution spectroscopy (LRS) by simulating James-Webb space telescope (MIRI + Nirspec) transmission spectra. We then developed our model to make it able to use high resolution spectroscopy (HRS) to simulate high resolution spectra (Spirou and Espresso in this work). Our aim is to give to the observers quantitative clues to know what type of retrieval model to use and what biases to expect depending on the type of planet and the spectral resolution of the instrument (LRS or HRS).