Studying Venus-like atmospheres with a GCM to address observational prospects of close-in orbit hot rocky exoplanets

International audienceA new era for characterization of Earth-like exoplanet atmospheres by transmission spectroscopy will be opened by the James Webb Space Telescope (JWST), scheduled for launch in 2021, and ARIEL, one of the three candidate missions selected by the ESA due for launch in 2028. In the perspective of detecting and characterizing more and more close-in-orbit hot terrestrial exoplanets transiting nearby small stars (e.g best Earth-size targets for transmission spectroscopy studies), the atmosphere of Venus is one of the most relevant cases to address observational prospects. We propose here to use Venus-like atmosphere templates based on a state-of-the art Venus General Circulation Model (GCM) [1, 2] with the goals of: 1) studying how the planet's atmosphere modifies the observable and 2) showing the potential and limitation of detecting spectral molecular signatures during a transit of Venus-like planet around a M star. In particular, we will focus here on theoretical transmission spectra of Venus-analogue exoplanet atmosphere as observed by forthcoming space-based satellites