Dr. Ian-Lin Lai (賴彥霖博士)
國立中央大學天文所 博士後研究員
October 16, 2026 (Friday), 15:00
S4-917, Chien-Shiung Building

Abstract

        The tenuous atmospheres of the Moon and Mercury have been explored since the Apollo and Mariner eras. On these airless planetary bodies, the exosphere is gravitationally bound but essentially collisionless: atoms and molecules undergo far more interactions with the planetary surface than with one another. As a result, the surface plays an important role in controlling the transport, loss, and redistribution of exospheric species. Different species respond differently to surface temperature, solar radiation, solar-wind bombardment, and meteoroid impacts, leading to distinct spatial distributions and temporal variability. Understanding these gas–surface interactions is therefore essential for interpreting the composition and dynamics of surface-bounded exospheres. In this talk, I will review our current understanding of the lunar and Hermean exospheres with a focus on their sources, transport, and surface interactions. I will also discuss how these processes control the spatial distributions, composition, and temporal variability of exospheric species, and how observations from past and current missions have improved our understanding of these tenuous atmospheres.