Cosmos Seminar

Clearing the Haze: Photochemical Haze Modeling in Sub-Neptune Atmospheres

In this project, we create a modeling framework for hazy sub-Neptune exoplanets by extending the disequilibrium chemistry framework of Mukherjee et al. (2024) to include photochemically produced hazes. These models couple the open-source frameworks of PICASO, photochem, and VIRGA to compute atmospheric structures and spectra with a consistent treatment of chemistry, hazes, and radiation. Our models improve previous haze treatments by using lab-based optical constants and physical properties for the haze particles. We also include a microphysics model that follows the creation, growth, and settling of haze particles as they evolve in the atmosphere. By combining these improvements with the radiative transfer framework in PICASO, we generate predicted spectra for hazy sub-Neptunes. These models can help observers compare data with a broader set of theoretical predictions and clarify the atmospheric processes at work in this planet population. Ultimately, our goal is to advance understanding of how photochemical hazes form and shape observable properties in sub-Neptune atmospheres, which remain among the most common yet least-well-characterized exoplanets.