Astronomy

“Updating planetary reflectance models with polarimetry and improved surface and condensate representation for exoplanet characterization”

Abstract:
Terrestrial worlds are complex, with spatially varying surfaces and uneven condensate distributions. While studies of reflected light can provide clues about the nature of their atmospheres and surfaces, degeneracies remain. Clouds can obscure low altitude biosignatures, and high polar albedo (Cowan et al 2012) or equatorial cloud (Robinson et al 2010) can mimic ocean glint. Furthermore, many reflectance phase curves of planets do not consider the non-lambertian nature of the condensates and surfaces. We use polarimetry (measure of the orientation of the electric field of reflected light) and refined reflectance characterization to help diminish these degeneracies allowing the characterization of potentially habitable worlds. In this talk, I show validations of polarized radiative transfer codes with Earthshine data and Venus observations, finding and confirming that they are sensitive to biosignature gases, ocean glint, vegetation, condensate species and phase, and surface inhomogeneities (polar haze, ice caps, continents, etc.). I discuss further generalized models of likely terrestrial scenarios which provide albedo, angular reflectance, and polarization predictions to aid the imaging and phase curves future telescopes could obtain to map worlds and distinguish between condensates and surfaces. I relate this to our ongoing work to match models to observations of hot Jupiter planet reflectance signatures, and highlight the importance of more nuanced and physically robust models representing their condensates’ optical behavior.

Dr. Kim Bott, University of California, Riverside

Thursday, October 27, 2022 @ 12:45 PM – 1:45 PM EST
Zoom Meeting ID: 942 3296 7732

Join Zoom Meeting
https://ufl.zoom.us/j/94232967732

Sign up to meet with Dr. Bott, please find a spot in her Thursday calendar here:
UF Astronomy colloquium (Kim Bott)