HIGH-ACCURACY HIGH-TEMPERATURE PRESSURE BROADENING AND LINE POSITIONS FOR MODELING H2O AND IN EXOPLANET ATMOSPHERES

Gharib-Nezhad, Ehsan

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https://hdl.handle.net/2142/104416 Copy

Description

Title

HIGH-ACCURACY HIGH-TEMPERATURE PRESSURE BROADENING AND LINE POSITIONS FOR MODELING H2O AND IN EXOPLANET ATMOSPHERES

Author(s)

Gharib-Nezhad, Ehsan

Contributor(s)

Bechtel, Hans A; Line, Michael R; Lyons, James R; Heays, Alan

Issue Date

2019-06-21

Keyword(s)

Lineshapes, collisional effects

Abstract

Infrared line positions and pressure-broadening data of atmospheric key absorbers \chem{H_2O} and \ce{CH_4} strongly impact the interpretation of exoplanetary observational data. The inaccuracy of absorption cross-sections (opacity data) biases atmospheric radiative transfer modeling. The detection of \chem{CH_4}, for instance, is still under debate, despite extensive endeavors to model the chemical composition of exoplanetary atmospheres. To this end, we are carrying out the following projects. First, high-resolution high-temperature \chem{H_2}-pressure-broadened spectra are recorded for the \chem{CH_4} \nub{3}-band P-branch. Measured linewidths for 112 transitions between 2840 and 3000 cm$^{-1}$ with temperature and pressures ranging between 300 and 700 K, and 10 and 933 Torr, respectively, were used to find rotation- and tetrahedral-symmetry-dependent coefficients for pressure and temperature broadening and pressure-induced lineshifts. Second, we are currently investigating the impact on \chem{H_2O} absorption cross-sections of various line lists (e.g., POKAZATEL vs. BT2). We assess the potential bias when interpreting the cross-correlation function through Earth-based observations. We report our progress in measuring high-temperature \chem{H_2O} line positions.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

English

Permalink

http://hdl.handle.net/2142/104416

DOI

10.15278/isms.2019.FE07

Copyright and License Information

Copyright 2019 Ehsan Gharib-Nezhad

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