Assessing the Impact of H2O and CH4 Opacity Data in Exoplanetary Atmospheres: Laboratory Measurements and Radiative Transfer Modeling Approaches

• Other Authors: Gharib-Nezhad, Ehsan (Author)
• Format: Doctoral Thesis
• Language: English
• Published: 2019
• Subjects: Atmospheric chemistry; Astrophysics; Physical chemistry; Exoplanets (Extrasolar planets); Infrared Spectroscopy; Methane (CH4); Opacity (Absorption Cross-Sections); Pressure-broadening; Water (H2O)
• Online Access: http://hdl.handle.net/2286/R.I.54982

abstract: One strategic objective of the National Aeronautics and Space Administration (NASA) is to find life on distant worlds. Current and future missions either space telescopes or Earth-based observatories are frequently used to collect information through the detection of photons from exoplanet atmospheres. The primary challenge is to fully understand the nature of these exo-atmospheres. To this end, atmospheric modeling and sophisticated data analysis techniques are playing a key role in understanding the emission and transmission spectra of exoplanet atmospheres. Of critical importance to the interpretation of such data are the opacities (or absorption cross-sections) of key molecules and atoms. During my Doctor of Philosophy years, the central focus of my projects was assessing and leveraging these opacity data. I executed this task with three separate projects: 1) laboratory spectroscopic measurement of the infrared spectra of CH4 in H2 perturbing gas in order to extract pressure-broadening and pressure-shifts that are required to accurately model the chemical composition of exoplanet atmospheres; 2) computing the H2O opacity data using ab initio line list for pressure and temperature ranges of 10^-6–300 bar and 400–1500 K, and then utilizing these H2O data in radiative transfer models to generate transmission and emission exoplanetary spectra; and 3) assessing the impact of line positions in different H2O opacities on the interpretation of ground-based observational exoplanetary data through the cross-correlation technique. === Dissertation/Thesis === Doctoral Dissertation Chemistry 2019