Assistant Professor, Earth and Space Sciences

AB Degree Track
Dual-Title PhD

Origin & Evolution of Life on Earth
Exoplanets: Detection, Habitability, & Biosignatures




Joshua Krissansen–Totton

2019 – PhD in Earth and Space Sciences and Astrobiology, University of Washington (USA)
2012 – BSc(Hons) in Physics, University of Auckland (New Zealand)

Current Research:
The fundamental question driving my research is whether life exists elsewhere in the universe. In the coming 5-10 years, the characterization of terrestrial exoplanets will grow immensely as a scientific field. There will soon come a time when researchers specialize in individual exoplanetary objects, just as current planetary scientists specialize in solar system bodies. This coming windfall of planetary environments beyond the solar system will greatly expand the search for life. However, the interpretation of exoplanet observations demands an understanding of planets not merely as astrophysical objects, but instead as planetary bodies with rich geological, geophysical, and geochemical histories. It will be necessary to carefully apply Earth and planetary science knowledge in the form of quantitative models to make testable predictions.

I specialize in modeling the biogeochemical evolution of terrestrial planets, including interactions between atmospheres, surfaces, and interiors. My current research combines Earth system science, namely models of carbon and oxygen cycling in deep time, with an awareness of astronomical observations to formulate testable hypotheses about terrestrial planet atmospheres and biosignatures.

Recent Publications:
A complete list is available here

Selected Recent Publications (*=student mentee):

Krissansen-Totton, J. and Fortney, J. J. (2022). Predictions for Observable Atmospheres of Trappist-1 Planets from a Fully Coupled Atmosphere–Interior Evolution Model. The Astrophysical Journal 933 115. DOI: 10.3847/1538-4357/ac69cb

Thompson*, M., Krissansen-Totton, J., M., Galloway*, Wogan, N., Telus, M., Fortney, J. J. (2022). The Case and Context for Atmospheric Methane as an Exoplanet Biosignature. Proceedings of the National Academy of Sciences USA. DOI: 10.1073/pnas.2117933119.

Krissansen-Totton, J., Thompson*, M., Galloway*, M., Fortney, J. J. (2022). Understanding planetary context to enable exoplanet life detection and test the Copernican principle. Nature Astronomy. DOI: 10.1038/s41550-021-01579-7.

Krissansen-Totton, J., Fortney, J. J., Nimmo, F. (2021). Was Venus ever habitable? Constraints from a coupled interior-atmosphere-redox evolution model. The Planetary Science Journal. DOI: 10.3847/PSJ/ac2580.

Krissansen-Totton, J., Fortney, J. J., Nimmo, F., Wogan, N. (2021). Oxygen false positives on habitable zone planets around sun-like stars. AGU Advances, 2, e2020AV000294. DOI: 10.1029/2020AV000294.

Krissansen-Totton, J., G. Arney, D. C Catling (2018). Constraining the climate and ocean pH of the early Earth with a geological carbon cycle model, Proceedings of the National Academy of Sciences USA, DOI:10.1073/pnas.1721296115.

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