Date: Monday 03-Feb-2020
Time: 11:15-12:15
Location: ATL 1250
Speaker: Christian Eistrup (UVA)
Title: From Protoplanetary Disk to Exoplanet Atmospheres and Comets - The Chemical Link
Exoplanets are ubiquitous, and exoplanetary science is now pushing to constrain the atmospheric compositions of exoplanets. This quest will be further aided by the next generation of facilities, such as the JWST and ground-based ELTs. Linking the observed composition of exoplanet atmospheres to where and how they formed in their natal protoplanetary disks often involves comparing the observed exoplanetary atmospheric carbon-to-oxygen (C/O) ratio to a model of a disk midplane with a fixed chemical composition. In this scenario, chemical evolution in the midplane prior to and during the planet formation era is not considered. The C/O ratios of gas and ice in the disk midplane are simply defined by icelines of volatile molecules such as water and CO in the midplane. However, kinetic chemical evolution during the lifetime of the gaseous disk can change the relative abundances of volatile molecules, thus altering the C/O ratios of the planet-forming material. In my chemical evolution models, I utilize a large network of gas-phase, grain-surface and gas-grain interaction reactions, thus providing a comprehensive treatment of chemistry. In my talk, I will show how such chemical reactions can cause the chemical composition in the disk midplane to evolve, and how this affects the C/O ratios of the gas and solid material that form planets and comets. I will argue that chemical evolution in both gas and ice in the disk midplane needs to be addressed when linking the chemical makeup of observed exoplanet atmospheres to how the exoplanets formed in their natal disks, as well as for understanding ice compositions in Solar System comets.
For further information contact PALS coordinator Dr. Lori Feaga at feaga@astro.umd.edu or (301)-405-1383.
SPECIAL ACCOMMODATIONS:Special accommodations for individuals with disabilities can be made by calling (301) 405-3001. It would be appreciated if we are notified at least one week in advance.
