Chemistry of Brown Dwarfs, Exoplanets, and Low-Mass Stars

Washington University, Saint Louis MO

Investigators

Abstract

The PI and her team will take atmospheric chemistry techniques that they previously used to model planets in our solar system, and apply them to the study of low-mass stars, brown dwarfs (objects with masses between that of stars and planets) and exoplanets (planets outside of our solar system). These objects all have in common that they are low enough temperature (T < 2600 K) to undergo molecular gas- and cloud-chemistry. One focus of this project will be on the effects that chemical compositions different from the Sun have on the atmospheric chemistry of these objects. They will also investigate the deuterium chemistry to help define the planet-star boundary. The team will develop a web-based platform for the thermodynamic data resulting from these studies, which is relevant to scientists in astronomy, planetary science, geochemistry, chemical engineering, materials science as well as industry. They will train and mentor a graduate student and undergraduate students in research, including those majoring in computer science through a cross-campus intitiative. Scientific results will be integrated into new and revised textbooks. The investigators will accomplish this by carrying out thermochemical and kinetic computations to study gas and condensate speciation at different metallicities and varying C/O ratios and to identify possible chemical metallicity indicators. They will then apply results from the computations to hot irradiated gas giant exoplanets, and M&L dwarfs and subdwarfs. They will also work with collaborators to expand models of photometric and spectroscopic signatures of clouds and metallicity effects. The deuterium (D) chemistry work will be done by deriving the thermodynamic and rate data for D/H exchange reactions, expanding the existing computational schemes; running the computations and analyzing the results for the most abundant and/or spectroscopically active D-bearing gases.