This thesis addresses the chemical processes that determine the compositions of giant planet atmospheres. Connecting the observed composition of exoplanets to their formation sites often involves... Show moreThis thesis addresses the chemical processes that determine the compositions of giant planet atmospheres. Connecting the observed composition of exoplanets to their formation sites often involves comparing the observed planetary atmospheric carbon-to-oxygen (C/O) ratio to a disk midplane model with a fixed chemical composition. In this scenario chemistry during the planet formation era is not considered, and the C/O ratios of gas and ice in disk midplane are simply defined by volatile icelines in a midplane of fixed chemical composition. However, kinetic chemical evolution during the lifetime of the gaseous disk can change the relative abundances of volatile species, thus altering the C/O ratios of planetary building blocks. 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 chemical evolution can modify disk miplane chemistry and how this affects the C/O ratio of giant planet-forming material. I will argue that midplane chemical evolution needs to be addressed when predicting the chemical makeup of planets and their atmospheres. And as an extra, I will propose that chemical evolution can help constrain the formation histories of comets. Show less
This thesis is centered around the embedded phase of star formation and the chemical links between the various stages of evolution. The primary goal of this work is to pinpoint the origins... Show more This thesis is centered around the embedded phase of star formation and the chemical links between the various stages of evolution. The primary goal of this work is to pinpoint the origins of cometary complex organic molecules in the preceding protoplanetary disk and prestellar stages, both in the gas and solid phases. The grand motivation is to identify our interstellar roots. This work is unique in comparison to earlier publications due to the dynamic nature of the models used in combination with the large comprehensive chemical network. Three chapters in this book pertain to physicochemical models and an additional one is of observational nature. Altogether, this thesis is an attempt to piece together the chemical connection between the prestellar core, the protoplanetary disk and the protoplanetary and cometary materials. The main take-home message is that the seeding of infant Solar System building blocks with complex organic molecules is unavoidable as a result of chemistry during protoplanetary disk assembly. Show less
