Associate Professor, Earth-Life Science Institute, Institute of Science Tokyo
I study how the interiors of ocean worlds evolve chemically over geological time, and whether that evolution can sustain the conditions life requires. My approach couples thermodynamic and reactive-transport modeling with laboratory measurements, so that predictions about a planet's interior chemistry can be tested against observation rather than left as speculation.
Much of this work concerns rock-water reactions: how water alters primordial minerals, what gases and solutes are released, and whether the resulting chemical disequilibrium could support metabolism. I began by applying these methods to early Mars, using meteorite mineralogy and paleolake deposits to reconstruct the planet's water and carbon budget before its climate collapsed. Since 2018 the same framework has extended to icy ocean worlds (Europa, Ceres, Enceladus, Titan, and the moons of Uranus) where rock metamorphism, rather than tidal heating alone, can generate and sustain chemical energy long after a body's initial ocean forms.
A prediction from this work, that Europa's ocean should be enriched in CO2 from metamorphic outgassing, was confirmed by JWST observations in 2023; coupling interior geochemistry to observable surface and atmospheric signatures gives testable, falsifiable constraints on habitability, rather than qualitative arguments about what a planet might be like.
I am increasingly interested in what this framework can say about sample-return science and mission-relevant targets, where interior models meet what a lander or returned sample can actually measure, and in extending coupled evolution modeling toward exoplanet interiors.
All three are open source and used by other groups in the ocean worlds and geochemistry communities.
I have supervised 18 students and postdocs (four PhD students, eight postdocs, six undergraduate interns), several of whom are now at UCLA, Arizona State University, JPL, Marum/U Bremen, and beyond. I lecture in the International Graduate Program at ELSI, Science Tokyo.
I welcome inquiries from prospective students and postdocs whose interests intersect thermodynamics, geochemistry, and planetary interiors. See contact details below.
37 peer-reviewed papers. Titles link to the paper on the journal's site; a fuller record (with category tags) is in the CV (PDF).
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