A Temperature Trend for Clouds and Hazes in Exoplanet Atmospheres

Abstract The transmission spectra of exoplanet atmospheres observed with the Hubble Space Telescope (HST) in near-infrared range (1.1–1.65 ? m) frequently show evidence for some combination clouds and hazes. Identification systematic trends hazes is potentially important understanding atmospheric composition temperature structure. Here we report on analysis spectral modulation using a large, uniformly processed sample HST/WFC3 transit from 62 exoplanets. retrieval includes capability to detect represent which departs thermochemical equilibrium. By this unique catalog measuring dampening modulations compared strictly clear atmospheres, identify two populations. One completely cloud/haze free spanning wide range, while other population, identified as “partial cloud/hazes,” follows trend mostly cloudy/hazy around 500 K at ?1500 K. We also find that partially transparent aerosol component present it typically vertically distributed throughout column. Our findings suggest are common majority planets have level detectable modulation. Additionally, empirical minimized 1460.86 ? 405 + 316 revealed our has predictive utility modeling performance large-scale transiting exoplanets survey, such planned Ariel mission. This can be used making probability-based forecast given source context future JWST observations. Future observations including optical and/or broader coverage may useful further quantify reported here.