Dr. Akash Gupta, Princeton University

Title: Connecting the Dots: From Electrons to Planets

Abstract: The most common planets observed to date fall between the sizes of Earth and Neptune. I will present how my work, together with recent studies, demonstrates that most of these planets accreted hydrogen-helium envelopes from their protoplanetary disks. Over millions to billions of years, some lose these primordial atmospheres through escape processes and emerge as rocky super-Earths, while those that retain their envelopes correspond to the population observed today as sub-Neptunes.

This evolutionary pathway has profound implications for interpreting the diversity of atmospheres now being revealed by the James Webb Space Telescope and for designing future surveys. In particular, these hydrogen-helium-dominated atmospheres are expected to interact strongly with their molten or supercritical interiors over much of their lifetime. Yet, despite their central role in planetary evolution, our fundamental understanding of these atmosphere-interior interactions remains limited, largely because they occur under extreme pressures and temperatures that are difficult to access experimentally.

I will present new quantum-mechanical insights into how key planetary materials — hydrogen, helium, water, silicates and iron — interact and transform under conditions relevant to Earth-to- Neptune-mass planets. I will discuss how these results challenge long-held views on the evolution and structure of planets and outline their implications for interpreting current and future observations, including those from JWST, as well as upcoming missions and facilities such as the Uranian Orbiter and Probe, the Habitable Worlds Observatory and ELTs.