Yeon Joo Lee
Technische Universität Berlin, Germany

Abstract
Characterization of exoplanets' atmospheres is necessary to better understand the habitability in extrasolar systems. I would like to introduce one of such efforts, investigating Venus, as an exoplanet, which aims to understand observational properties of its 20-km thick clouds from a far distance using the data of the Akatsuki spacecraft. We find Venus' global brightness modulations with two periods at ~4 and ~5 days. This is caused by the atmosphere; the thick clouds of Venus hide the surface rotation (243 days) and alter the planetary brightness by winds and atmospheric waves that drift atmospheric absorbing agents. This is a clear distinction from that of the Earth, which has a prominent planet's rotation rate (1 day). We also identify characteristic behaviors of Venus’ brightness in terms of temporal and spectral variabilities. These overall properties will help a diagnosis of the existence of "thick atmosphere" on terrestrial exoplanets, which should be possible to observe with future exoplanet missions that have direct imaging capability. The results are published at Nature Communications (https://www.nature.com/articles/s41467-020-19385-6). At the end of the talk, I would like to introduce ongoing Venus faraway observations from ESA-JAXA's BepiColombo spacecraft during its cruise to Mercury.

2021 February 03, 13:30

IA
Online broadcast (Zoom)