Graduate Fellows

Juan David Hernández-Montenegro

Graduate Student, Geology

I'm Juan David Hernández-Montenegro, a grad student in Geology, working with Paul Asimow on the thermal evolution of Mars. My research focuses on analyzing Martian meteorites and in-situ data from exploration rovers to understand how Mars' mantle has evolved over time. I develop models to reconstruct the magmas produced by the Martian mantle, aiming to determine the conditions of their formation. Part of my research includes studying the magmas that generated igneous formations in Jezero crater, using data from the PIXL instrument on the Perseverance rover. This work helps in understanding the geological processes on Mars, contributing to our knowledge of the planet's history and its environment.

Kimberly Paragas

Graduate Student, Planetary Science

I am a graduate student in Planetary Science working with Heather Knutson and Renyu Hu. I am broadly interested in probing the atmospheres of exoplanets to learn about their formation and evolution. I am currently developing a new framework to simultaneously retrieve atmosphere and surface properties of hot, rocky exoplanets using their emission spectra measured by JWST in the mid-infrared. Soon, I will be working in the lab to obtain high temperature (~1000 K) spectra of minerals to establish a new spectral library to better model and understand the emission spectra of these hot, rocky worlds.

Rebecca Wipfler

Graduate Student, Geobiology

I'm a graduate student in Geobiology working with Dr. Jennifer Jackson and Dr. Victoria Orphan. I am broadly interested in environmental microbiology and understanding the limits of life under in situ extreme conditions, such as high hydrostatic pressure, extreme temperature (high or low), and salinity gradients. This is imperative to study as the majority of Earth's biosphere is under multiple, simultaneous extreme environmental conditions, but our current understanding of how combinations of these parameters affect microbial viability and activity is insufficiently constrained. To address this knowledge gap, I am using diamond anvil cells and fluorescence indicators to make spectroscopy measurements and quantify microbial activity at the single-cell level, allowing for observations of microbial responses under combinations of extreme conditions.

Simon Andren

Graduate Student, Geochemistry

I am a graduate student in Geochemistry, working with John Eiler and Woody Fischer. My academic interests are rooted in the application of emerging machine-learning techniques to address challenges within the realm of geochemistry. Currently, my research is focused on understanding the fractionation of stable isotopes in complex chemical systems, and the potential of using stable isotope measurements to differentiate between biogenic and abiogenic molecules. More specifically, I am developing a predictive model of the equilibrium isotope fractionation factor for organic molecules.

Jonathon Gomez-Barrientos

Graduate Student, Planetary Science

I am a graduate student in Planetary Science working with Heather Knutson and Katherine de Kleer. My current research focuses on confirming planet candidates that were first identified by NASA's Transiting Exoplanet Survey Satellite. I accomplish this goal by conducting follow-up transit observations with the 200-inch Hale Telescope at Palomar Observatory. With the TESS and Palomar observations, we can constrain stellar and planetary properties and use them to explore potential planet formation pathways.

Elizabeth Heiny

Graduate Student, Geology

I am a graduate student in Geology working with Paul Asimow and Ed Stolper. I have broad interests in terrestrial planet formation and the evolution of magmatic systems, and I aim to apply experimental petrology as a tool for planetary exploration. Currently, I am conducting partitioning experiments to calibrate an activity-composition model for amphibole, a hydrous phase that plays a key role in subduction zone processes and Earth's water cycle over geologic timescales. I am also characterizing the sulfur isotope signatures of troilite in the HEDs with SIMS analysis.

Valeria Kachmar

Graduate Student, Planetary Science

I am a graduate student in Planetary Science with broad interests in the formation and evolution of inner solar system bodies, working with Bethany Ehlmann and Konstantin Batygin. My current research aims to combine spectroscopy and spectral modeling to study surface water ice on airless planetary bodies. Ice can exist in different forms on planetary surfaces (frosts, slabs, or mixtures with regolith), and each of these scenarios tells us how it formed and accumulated. I have been conducting this scenario-wise approach to study ice on Ceres and the Moon, probing into their volatile history and the role of the space environment in forming and liberating planetary volatiles.

William Lawrence

Graduate Student, Geochemistry

I'm a graduate student in Geochemistry working with Bethany Ehlmann, George Rossman, and John Eiler. My current research projects range from using IR and Raman spectroscopy to inform how water and heat influenced the formation of primitive carbonaceous chondrite meteorites, and how such trends may be detected in related asteroids, to studying H isotopes in lunar meteorites. I am also broadly interested in topics such as biomarker preservation, impact cratering, and tectonics. Away from research you'll find me skiing or mountain biking somewhere nearby!

Maria Schmeer

Graduate Student, Geology

I am a graduate student in Geology working with Mike Lamb and Ruby Fu. I am interested in the dynamic processes that shape the surfaces of Earth and other planets and, in particular, ice-rich environments. Currently, I am working to develop a fine-scale, process-based model of fluid flow and phase changes through ice-bearing porous media. I aim to better understand the physical processes of ice formation and dissociation within pore spaces and the implications for hydrologic models of permafrost-rich regions and resulting landscape evolution.

Yuri Tamama

Graduate Student, Geophysics

I am a graduate student in Geophysics, working with Allen Husker, Jennifer Jackson, and Jean-Philippe Avouac. I am broadly interested in using seismology to understand the surface and interior processes of Earth and other planetary bodies. One of my projects focuses on the lunar seismic data collected by Apollo 17. I aim to constrain the mechanisms causing seismic activity to better understand the processes that shape the lunar surface. Furthermore, given that seismic waves probe the lunar surface and interior, I can also work towards uncovering their material properties and composition.

Tony Yap

Graduate Student, Planetary Science

I am a graduate student in Planetary Science working with François Tissot and Konstantin Batygin. My research is centered on early Solar System evolution, as explored through isotopic signatures of meteorites and modeling of protoplanetary disks. With FT, I am using nucleosynthetic isotope anomalies to trace genetic ties between Solar System materials. With KB, I am evaluating the efficiency of competing modes of planet formation in different regions of disks.

Eran Funaro

Graduate Student, Geology

I am a graduate student in Geology working with George Rossman and Paul Asimow to quantify and understand the radiative heat flow through earths rocky mantle. Recent observations suggest that the radiative heat flow through earth's mantle is not negligible as previously thought. We will test the sub-atomic mechanism (IVCT) previously thought to absorb the radiative heat flow by measuring IR absorbance of mantle building minerals at mantle temperatures and pressures. I am interested both in widening our understanding of sub-atomic chemistry and in scaling up these understandings to planetary scale to shed light on the anatomy and evolution of bodies across and beyond the Solar System.

Emily Geyman

Graduate Student, Geology

I am a graduate student in Geology working primarily with John Grotzinger. I am interested in using sedimentary records to reconstruct Earth's ancient environments. In particular, I am interested in how we can use the morphology of stromatolites preserved in the rock record to reconstruct the physical, chemical, and biological conditions at the ancient seafloor.

Abigail Keebler

Graduate Student, Planetary Science

I am a graduate student in Planetary Science working with Bethany Ehlmann and Ken Farley. I have broad interests in planetary surface processes and environmental evolution on terrestrial planets and rocky moons. Currently, I am using spectroscopy to constrain the mineralogy of dust source regions on Earth. I am also a member of the Mars 2020 science team.

Noam Lotem

Graduate Student, Geochemistry

I am a graduate student in Geochemistry, working with John Eiler and Woody Fischer. I am interested in the application of stable isotope methods as tools for discerning between biogenic and abiotic molecules, for determining the boundaries of life on Earth and searching for extraterrestrial life. Towards this goal, I am developing and applying novel ‘clumped' isotope methods to examine the composition of simple molecules that are products of microbial metabolism. Currently, I am developing a framework for measuring and interpreting the clumped isotope composition of microbially produced H2.

Zachariah Milby

Graduate Student, Planetary Science

I am a graduate student in Planetary Science with broad interests in planets and their atmospheres. I work with Katherine de Kleer analyzing Keck/HIRES observations of aurora on Ganymede and the other icy Galilean satellites. We compare the relative brightness of the auroras to models to gain insight into the tenuous oxygen atmospheres of these distant worlds.

Jessica (Jess) Mueller

Graduate Student, Geochemistry

I am a graduate student in Geochemistry working with Bethany Ehlmann, Francois Tissot, and Katherine de Kleer. I aim to increase our fundamental understanding the solar system's mineralogical evolution and isotopic variability through time by studying early solar system materials. My current work is focused on utilizing near and mid-infrared spectroscopy to characterize the nature and abundance of Calcium-Aluminum-rich inclusions (CAIs) in asteroids. Building this spectroscopic framework for CAIs will be useful when interpreting mid-infrared observations from the JWST.

Yu Yu Phua

Graduate Student, Planetary Science

I am a graduate student in Planetary Science working with Bethany Ehlmann and Katherine de Kleer. My current works focus on understanding the materials that make up planetary bodies, through the use of laboratory analog measurements, in-situ rover data, and thermal modelling of global surface properties. I am interested in how these different methodologies that give information at different spatial scales can complement each other to better constrain the composition of planetary surface materials.

Morgan Saidel

Graduate Student, Planetary Science

I am a graduate student in Planetary Science working with Mike Brown and Heather Knutson. My research interests are primarily in studying the formation and evolution of planetary systems. With Mike Brown, I study the formation and evolution of the outer Solar System by probing the surfaces of Trojan asteroids. With Heather Knutson, I observe atmospheric loss on exoplanets in order to understand how exoplanetary systems evolve. When I'm not doing research, I enjoy backpacking, gardening, and surfing.

Jiani Yang

Graduate Student, Environmental Science & Engineering

I'm a graduate student in Environmental Science and Engineering working with Professors Yuk Yung and John Seinfeld. I am interested in studying planetary atmosphere to understand planets within and beyond the solar system to answer important questions such as "Where did we come from?" and "Are we alone?". Towards this goal, I am working on DSCOVR data to derive vegetation signal in light curves of the sunlit disk of the Earth to evaluate the habitability of exoplanets.

Ryleigh Davis

Graduate Student, Planetary Science

I am a graduate student in Planetary Science working with Mike Brown. My research aims to combine spectroscopy from ground and space-based telescopes with laboratory experiments and spectra to identify the presence of specific salt species and disentangle their origin and potentially complex history and role within the surface chemistry of icy satellites. In particular, I am interested in probing the surface composition of Jupiter's icy moon Europa, which we hope to use as a window towards understanding the chemistry of its subsurface, salty ocean.

Julie Inglis

Graduate Student, Planetary Science

I am a graduate student in Planetary Sciences primarily working with Heather Knutson. My goal is to understand the formation and evolutionary pathways of giant planets on extreme orbits by using spectroscopy to characterize their atmospheres. My work involves a variety of techniques using both ground-based telescopes like Keck and space-based telescopes such as HST and JWST to probe the molecular abundances and structure of these atmospheres, which we can then compare with predictions from formation and evolutionary models.

Hemani Kalucha

Graduate Student, Geobiology

I am a graduate student in Geobiology working with Mike Brown, and co-advised by Woody Fischer. I am interested in life detection on the surface of Europa and how we can determine the origin and age of organic signatures on the surface with spectroscopy. Towards this goal, I create bacteria ice mixtures maintained at Europa surface pressure and temperature and irradiate them to understand how bacteria are chemically changed by radiation in an ice matrix using Raman and infrared spectroscopy.

Jocelyn Reahl

Graduate Student, Geology

I am a graduate student in Geology working with Michael Lamb. I am interested in how cold climates and ices uniquely shape planetary surface environments. In particular, I study the effect of perennially frozen ground—or permafrost—on Arctic river bank stability and sediment transport by using a combination of field measurements and hyperspectral remote sensing data to quantify fluvial sediment fluxes.

Christina (Tina) Seeger

Graduate Student, Geology

I am a graduate student in Geology working with John Grotzinger to understand the history of water on Mars--particularly the movement of groundwater during and after surface water flow--using data from the Curiosity rover as it investigates the geology of Gale crater. I'm interested in understanding links between surface processes on Earth, Mars, and bodies across the Solar System.

Noah Tashbook

Graduate Student, Geobiology

I am a graduate student in Geobiology studying astrobiology and paleontology with Professors John Eiler and Joe Kirschvink, looking at the co-evolution of life and Earth environments through deep time, with a particular focus on biomineralization and post-depositional metasedimentary processes. We use stable isotope geochemistry and paleomagnetic tools to constrain and reconstruct the early Earth and protoplanetary disk of both our solar system and exoplanetary systems. Our research utilizes a wide range of samples, from bacterial microfossils to asteroidal dust grains to biotissues from extant organisms. I am also interested in how the biosphere affects global biogeochemical cycles.

Jerry Xuan

Graduate Student, Astronomy

I am a graduate student in Astronomy working with Dimitri Mawet, and co-advised by Heather Knutson. I am interested in understanding how giant planets form and evolve, and how they shape and influence their natal planetary systems. Towards this goal, I've been studying giant planet and brown dwarf atmospheres using high-resolution spectroscopy from Keck and measuring their dynamical masses and 3-D orbits using astrometry, radial velocity, and imaging data.