10:00 AM - 10:15 AM
[PAE20-05] Mineral clouds of fluffy aggregates: how they form in exoplanetary atmospheres and influence transmission spectra
Keywords:Exoplanet, Cloud, Transmission spectrum
In this study, we investigate the influences of the particle porosity on vertical profiles of the clouds using a microphysical model taking into account the vertical transport, particle growth, and porosity evolution of cloud particles. We will demonstrate that the particle density can be lower than the material density by 2–3 orders of magnitude. As a result, the vertical extent of the clouds is potentially much larger than that expected in previous studies. We also calculate synthetic transmission spectra with fluffy-aggregate clouds. The fluffy-aggregate clouds largely obscure molecular signatures in the spectra and produce a characteristic spectral slope in visible to near-infrared wavelength. Finally, we compare the synthetic spectra with the transmission spectrum of GJ1214b, a super-Earth suggested to have clouds at ~0.01mbar in pressure, and find that the observed spectra can be explained by the mineral cloud of fluffy aggregates if atmospheric metallicity is higher than 100 times solar abundance. The predicted high atmospheric metallicity might encapsulate information about the formation process of GJ1214b.