Exploring Temperature Dependence on Optical Properties: Data to Inform Exoplanet Modeling

JACOPO TERRAGNI, Erika Kohler, Vincent Kofman, NASA Goddard Space Flight Center

     Abstract Number: 342
     Working Group: Aerosol Physics

Abstract
Recent observations from James Webb Space Telescope (JWST) are advancing our understanding of exoplanet atmosphere composition, dynamics, structure, and formation processes. However, extracting valuable information from observations is not straightforward: atmospheric models need to be superimposed onto the acquired spectra to translate these observations into the physical and chemical features of the planet. Unfortunately, models are limited because of the lack of in situ laboratory data collected at conditions like the ones observed on exoplanets, and new laboratory data are desperately needed as parameters to advance state-of-the-art exoplanet atmospheric models. In particular, the optical properties of the variety of different atmospheric particles expected in extrasolar systems are still largely unknown, especially at high temperatures that can be found in exoplanetary atmospheres. Despite the accuracy of the current and future observations, this fact fundamentally limits the characterization of observed exoplanets. Our project aims to address this lack of data by providing optical properties measurements of a diverse variety of particles, at temperatures representative of exoplanets observations, and make them available for the exoplanet scientific community. This project is carried out at the Hot Environments Lab at NASA GSFC and the experimental apparatus for this spectroscopic study consists of a High Temperature High Pressure (HTHP) Cell integrated into an FTIR (Fourier Transform InfraRed) spectrometer. Here we present the dedicated sample preparation procedure, how transmission spectra are collected, and how the optical properties of these particles are retrieved from the acquired spectra via a Lorentzian dispersion method. Finally, we discuss our plans to integrate these data into the Planetary Spectrum Generator (PSG) optical data library to quantitatively explore the differences between spectra retrieved by using room temperature optical data compared with the high temperature data collected in this project.