Study of Atmospheric Ion Escape From Exoplanet TOI‐700 d: Venus Analogs
T. Nishioka, K. Seki, R. Sakata, K. Yamamoto, N. Terada, S. Sakai, H. Shinagawa, A. Nakayama- Space and Planetary Science
- Geophysics
Abstract
TOI‐700 d is the first Earth‐sized planet in the habitable zone (HZ) discovered by the Transiting Exoplanet Survey Satellite. Here, we assess whether a Venus‐like exoplanet at the TOI‐700 d location could retain an atmosphere for a time comparable to the age of the host star based on multispecies magnetohydrodynamics simulations. We investigate the effects of X‐ray and EUV (XUV) radiation from the host star, the interplanetary magnetic field (IMF) orientation, and the planetary intrinsic magnetic field. In unmagnetized cases, major ion loss is caused by O+ escape through a ring‐shaped region by the mass loading process after the ionization of the extended oxygen corona. As the IMF Parker spiral angle increases, the escape flux in the magnetotail shows stronger enhancement around the meridional current sheet, and the escape rate of molecular ions (