Using retrievals to unlock the cloudy mysteries of directly imaged exoplanets.

Retrieval methods are increasingly being employed for analysis of directly imaged exoplanet atmospheres. This technique statistically explores a variety of potential bulk and atmospheric model parameters that combine to best fit an observed spectrum. While this technique has produced ground breaking research, retrieving clouds remains a complex challenge. TauREx3 (Tau Retrieval of Exoplanets) is a Bayesian retrieval suite developed for application to spectroscopic observations of exoplanet atmospheres. TauREx3 has been expanded for analysis of near-infrared spectroscopy for a sample of directly imaged gas giant exoplanets and brown dwarfs that encompasses the L and T spectral types. This includes Beta Pic b, HR 8799cde, PSO 318, VHS 1256 b and 51 Eri b. Using this sample, we have tested different cloud parameterisations ranging from a simplistic power law to a more robust Mie opacity regime. We explored the implementation of non-uniform clouds, motivated by the substantial variability observed in relations to several of the aforementioned objects. We have also probed the impact of using different cloud particle size distributions and temperature-pressure profiles in an effort to explore the biases different retrieval setups may introduce. This testing of different retrieval frameworks is vital given the recent launch of JWST and the subsequent high-quality data it will soon provide. In this talk I will present a summary of the novel retrieval results from this work.