Description
Sub-Neptunes are the most abundant class of exoplanets found in the universe,
yet they have no analogue in our own Solar System. Understanding their atmospheres and the underlying physical processes remains of prime interest. Despite significant progress in exoplanet observations and modeling, many aspects of sub-Neptune atmospheres remain poorly constrained. In particular, their atmospheric evolution and the connection between processes occurring at different heights in the atmosphere remain largely unexplored.
In this work, we aim to investigate how gravitational fractionation in the middle atmosphere above the homopause affects atmospheric loss occurring in the upper atmosphere, and the implications of this interaction for the survival of atmospheres of exoplanets. To this end, we employ a hydrostatic photochemical model with updated H–He–O chemistry to study the effects of gravitational fractionation. This framework is coupled with a one-dimensional hydrodynamic model of atmospheric escape to examine the interaction between these two processes.
Our findings will shed light on how strong the coupling between these processes is, which key chemical processes are involved, and whether there are any inherent limitations to this interaction. The approach developed here can be extended to planets irradiated by strongly flaring M-dwarfs, where atmospheric loss is expected to be much more prominent.
| Speaker information | PhD 1st year |
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