The creation and use of a chemical kinetics code to model and understand the atmospheres of hot Jupiters
type: CreativeWork
description: Chemical compositions of exoplanets can provide key insights into their physical processes, and formation and evolutionary histories. Atmospheric spectroscopy provides a direct avenue to probe exoplanetary compositions. However, whether obtained in transit or thermal emission, spectroscopic observations probe limited pressure windows of planetary atmospheres and are directly sensitive to only a limited set of spectroscopically active species. It is therefore critical to have chemical models that can relate retrieved atmospheric compositions to an atmosphere's bulk physical and chemical state. To this end we present Levi, a chemical kinetics code for modelling exoplanetary atmospheres. Levi is constructed as a eulerian solver of a series of coupled 1-D continuity equations for the evolution of molecular species. Levi is able to calculate the gas phase hydrogen, oxygen, carbon, and nitrogen chemistry in hot Jupiters to produce abundance profiles of the planets’ atmospheres. We perform extensive testing of Levi to ensure its accuracy, including investigations of how both the boundary and initial conditions of the model could affect the final result, as well as comparing the thermochemical processes to the diffusional and photochemical processes. Levi underwent benchmarking by testing it against already existing codes of the same type, to ensure the code was consistent with previously produced models. We use Levi to run a suite of models across a range of metallicities to produce the abundance of a number of molecules in any hot Jupiter's atmosphere. Our parameter sweep covers metallicities between 0.1x and 10x solar values for the C/H, O/H and N/H ratios, and equilibrium temperatures of hot Jupiters between 1000K and 2000K. We link this parameter sweep to hot Jupiter formation and migration models from previous works to produce predictions of the link between molecular abundance and planet formation pathways, for the spectrally active molecules H2O, CO, CH4, CO2, HCN a…
abstract: Chemical compositions of exoplanets can provide key insights into their physical processes, and formation and evolutionary histories. Atmospheric spectroscopy provides a direct avenue to probe exoplanetary compositions. However, whether obtained in transit or thermal emission, spectroscopic observations probe limited pressure windows of planetary atmospheres and are directly sensitive to only a limited set of spectroscopically active species. It is therefore critical to have chemical models that can relate retrieved atmospheric compositions to an atmosphere's bulk physical and chemical state. To this end we present Levi, a chemical kinetics code for modelling exoplanetary atmospheres. Levi is constructed as a eulerian solver of a series of coupled 1-D continuity equations for the evolution of molecular species. Levi is able to calculate the gas phase hydrogen, oxygen, carbon, and nitrogen chemistry in hot Jupiters to produce abundance profiles of the planets’ atmospheres. We perform extensive testing of Levi to ensure its accuracy, including investigations of how both the boundary and initial conditions of the model could affect the final result, as well as comparing the thermochemical processes to the diffusional and photochemical processes. Levi underwent benchmarking by testing it against already existing codes of the same type, to ensure the code was consistent with previously produced models. We use Levi to run a suite of models across a range of metallicities to produce the abundance of a number of molecules in any hot Jupiter's atmosphere. Our parameter sweep covers metallicities between 0.1x and 10x solar values for the C/H, O/H and N/H ratios, and equilibrium temperatures of hot Jupiters between 1000K and 2000K. We link this parameter sweep to hot Jupiter formation and migration models from previous works to produce predictions of the link between molecular abundance and planet formation pathways, for the spectrally active molecules H2O, CO, CH4, CO2, HCN a…
author: Hobbs, Richard
language: eng
keywords: Astronomy, Exoplanets, Hot Jupiter, Atmospheres, Atmospheric composition, metallicity, Atmospheric model
license: http://purl.org/NET/rdflicense/allrightsreserved
date published: 2021-09-01
date modified: 2026-07-22T22:24:10Z
provider: Cambridge University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Cambridge

PropertyValue
property ID: DOI
value: 10.17863/CAM.81162