PLANETARY SCIENCE

ASTROBIOLOGY

Icy Moons: Potential Doors to Extraterrestrial Life

I work toward understanding past and present geochemical processes on icy moons in the outer solar system. My current "field" sites are Saturn's moons Enceladus and Titan, and Jupiter's moon Europa. Enceladus is an active body that erupts a plume of material into space from a subsurface ocean of liquid water. I am interested in the chemical composition of the ocean, geochemical controls on its composition, and whether the ocean could be a suitable environment for life. Titan has a thick nitrogen-methane atmosphere and lakes of liquid hydrocarbons on parts of its surface. My research on Titan is focused on the origin of its atmosphere and the hydrocarbon-based geochemistry that plays a role in shaping its geology. Europa has a stunning surface of disrupted icy terrains and mysterious colors. My interests pertaining to Europa mirror those for Enceladus, but I am also interested in how Europa and Enceladus might have diverged in their geochemical evolution.

Example papers: Short review, Enceladus book chapter, phosphorus geochemistry, carbon dioxide ice on Europa, Titan's cryogenic geochemistry

Giant Planets: Probes of the Early Solar System

The giant planets dominate the outer solar system. They must be major actors in the story of the solar system. Their atmospheres contain volatiles, such as noble gases, that can be traced to their formation. The challenge is to know how to "read the air" out there. I'm interested in how planetary formation processes can create links between the volatile compositions of planetary building blocks, such as comets, and the planets as we see them today. Uranus is of special interest as NASA is preparing to develop a new mission to the blue-green world. The atmosphere of Uranus likely contains many clues to the formation and history of Uranus.

Example paper: Saturn's upper atmosphere.

Kuiper Belt:
New Adventures in Deep Space

I have started working with astronomers who are looking at Kuiper Belt objects using the James Webb Space Telescope. To my amazement, new surface ices are being found, including rare isotopologues. This means that there are now opportunities to learn about the chemical history of bodies in the outermost zone of the solar system.

Example papers: Pluto's nitrogen, Pluto book chapter, deuterium discovered on large KBOs, Eris/Makemake geothermal gases.

Exoplanets: A Universal Geochemistry Awaits

The advent of the James Webb Space Telescope is enabling molecules to be found in the atmospheres of small planets beyond the solar system. It is mind-blowing that we can get this type of information from planets that are over 100 trillion miles away. This leads to numerous questions like where did these molecules come from, what do they tell us about conditions on the planet, and can they help us to understand if some of these planets might be habitable or even inhabited? We are living in a golden age of space exploration, and the next decade will be incredibly exciting as we start to see how diverse planet compositions can be. It is time for geochemical approaches to be brought to bear on exoplanetary science. Geochemistry offers quantitative frameworks for interpreting discoveries that will be made. I am building an exoplanets program and look forward to contributing to this community.

Example papers: K2-18 b disequilibria, TOI-270 d accepted version (this paper is relevant to K2-18 b).

Hydrothermal Organic Geochemistry: From the Kitchen of the Earth

I investigate the reaction mechanisms of organic compounds in hydrothermal systems. I am interested in how organic molecules are abiotically synthesized, transformed, and degraded in these environments. The goal is to understand the fundamental role of organic geochemical processes in the deep carbon cycle, on Earth and inside of other planetary bodies. Detailed information about reaction mechanisms is obtained by performing hydrothermal experiments, which are designed and analyzed using principles of physical organic chemistry. With any luck, this research might produce new insights into how the building blocks of life can emerge and perhaps evolve on suitable planets and moons.

Example paper: Hydrothermal decarboxylation.