Methylated Biosignatures
Primary Approaches: photochemical and spectral modeling
I use a series of photochemical (atmos, VULCAN) and spectral (SMART, PSG) models to perform vertically integrated simulations that examine the feasibility of novel biosignature candidates. Specifically, I am interested in outcomes from the methylation bioprocess which occurs through the attachment of a methyl (CH3-) group to an environmental substrate. This process is thought to be deeply rooted on the Earth and is associated with environmental detoxification, a key trait of life. Our results clearly demonstrate a continuation of the build up effect around M dwarfs, first shown by Segura et al., 2005. We also find a novel co-additive spectral effect where multiple methylated gases contribute to the same spectral region and enhance potential detectability of methylated gas features. For more information, you can read Leung et al., 2022 and view presentations on the Recorded Talks page.
I use a series of photochemical (atmos, VULCAN) and spectral (SMART, PSG) models to perform vertically integrated simulations that examine the feasibility of novel biosignature candidates. Specifically, I am interested in outcomes from the methylation bioprocess which occurs through the attachment of a methyl (CH3-) group to an environmental substrate. This process is thought to be deeply rooted on the Earth and is associated with environmental detoxification, a key trait of life. Our results clearly demonstrate a continuation of the build up effect around M dwarfs, first shown by Segura et al., 2005. We also find a novel co-additive spectral effect where multiple methylated gases contribute to the same spectral region and enhance potential detectability of methylated gas features. For more information, you can read Leung et al., 2022 and view presentations on the Recorded Talks page.
Photochemical modeling of terrestrial planet atmospheres
Primary approaches: model development & intercomparison
Through my work on methylated biosignatures (above) and collaborative projects, I have significant experience working on the development of the atmos model. This includes expansion of the chemical species and reaction networks to include halogen species and exploring the impact of parameters such as:
Through my work on methylated biosignatures (above) and collaborative projects, I have significant experience working on the development of the atmos model. This includes expansion of the chemical species and reaction networks to include halogen species and exploring the impact of parameters such as:
- The atmospheric height (Ranjan et al., 2023)
- endpoints of the internal wavelength grid used
- impact of modeled Lyman alpha line (Peacock et al., 2022)
Spectral modeling of terrestrial planet atmospheres
Primary approaches: Model intercomparison, ground and space based simulations
I have had the opportunity to work on a variety of spectral simulation projects utilizing different models, configurations, and goals. These include:
I have had the opportunity to work on a variety of spectral simulation projects utilizing different models, configurations, and goals. These include:
- Addressing oxygen false positive discrimination through simulation of high resolution spectra (Leung et al., 2020)
- Modeling Atmospheric Lines by the Exoplanet Community (MALBEC), a CUISINES model inter comparison project (Villanueva et al., in press). For this project, I have served as the point of contact for the SMART model and generated a variety of spectra for transmission cases of terrestrial and giant planets, including separate analysis of spectral contribution such as CIA, Rayleigh scattering.
- Simulation of instrumental noise and observations for a variety of telescopes including JWST, Origins, ELTs (Leung et al., 2020; 2022) and contribution of input spectra used in the LIFESim (Angerhausen et al., 2024).