Over the past two decades, atmospheric characterization of exoplanets and brown dwarfs has been dramatically increasing. The compositional and temperature diversity of these worlds provide a unique opportunity to gain insight into planetary atmospheric chemistry. Our understanding of this full gamut of data will hinge on our ability to link observations to theoretical models, and then our ability to link those models to fundamental molecular and atomic absorption cross-sections. Absorption cross-sections serve as a fundamental input to all models used for atmospheric chemical characterization. The limitation in the current cross-sections for modeling observed objects through the Hubble and James Webb Space telescopes, as well as the critical need for accurate spectral line position for high-resolution cross-correlation technique, could lead to serious uncertainties and biases on the interpreting the observational telescope. These include uncertainty in the C/O ratio, thermal structure, and atmospheric composition [e.g., Gharib-Nezhad et al. 2019, 2021]. Addressing these remarks, general differences of the current absorption cross-sections databases will be outlined. The status of a set of key atmospheric absorbers relevant to late-type stellar, brown dwarf, and planetary atmospheres will be discussed in detail. The noticeable disagreements between different line lists including H2O, CH4, CO2, as well as metal oxides such as TiO, and VO will be mentioned and their impact on synthetic emission/transmission spectra will be examined. Our long-term team effort to improve the accuracy of the main components of absorption cross-sections such as spectral line positions and pressure broadening coefficients will be discussed. In sum, an overview of the current challenges both in theoretical and laboratory fields and their practical influence on radiative transfer modelings will be outlined.

Challenges with characterizing extrasolar atmospheres through the eyes of a spectroscopist

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.