Dr. Nisha Katyal

n our quest to search for habitable extraterrestrial environments, understanding of the origin of habitable conditions on our own planet Earth is necessary. In this talk, I will discuss the atmospheric evolution of early Earth in interaction with its interior and how that differs from other terrestrial planets, such as Venus. In the present work, I use constraints on the water and carbon budget of early planetary mantle with its different redox states to study the evolution of atmosphere dominated by H2O, CO2, H2 and CO. I employed a coupled suite of numerical models such as convection-radiative atmospheric model, interior model, escape processes and a newly developed coupling mechanism: the redox evolution of the mantle to study the role of key processes such as outgassing and escape in determining the atmosphere of the early Earth. Our work suggests that (1) a massive steam atmosphere can prolong the cooling of the planet by several million years due to a runaway greenhouse effect, and (2) the redox condition of the magma ocean affects the redox state of subsequently formed mantle and the overlying atmosphere. This work provides useful insight into the development of Earth's atmosphere during the magma ocean period, as well as serves as an input to guide future studies of interior composition of exoplanets and their possible links with their atmospheric composition, which may be estimated from observed infrared spectra by future missions.