Jason Steffen
University of Nevada-Las Vegas, NV·Astronomy & Astrophysics
Every rocky planet is built from whatever elements the Galaxy had on hand when it formed. Those elements are not fixed: stars forge new ones and scatter them when they die, so the chemical mixture available to planet builders has shifted steadily since the first stars, starting from the primordial elements left by the Big Bang and growing richer in iron, silicon, magnesium and the rest over billions of years.
- Fields
Astronomy & Astrophysics
Physics
Earth & Environmental Science
- Topics
exoplanets
galactic chemical evolution
nucleosynthesis
- Grants
- 1 known grant, through Aug 2029
What they work on
- Model how galactic chemical evolution, the gradual enrichment of the Galaxy with elements forged in stars and their remnants, changes the raw material available to form rocky planets over cosmic time.
- Incorporate new prescriptions for stellar initial mass functions, element-synthesis timescales that depend on production site, and chemical mixing into simulations of planet formation across galactic history.
- Predict how bulk density, chemical composition, core presence and core-to-mantle mass fraction of rocky planets vary with formation time, including differential enrichment of planet-forming material.
- Determine from the models which planets could sustain a magnetic field, volcanism and plate tectonics, and what gases their outgassing would supply to an atmosphere, yielding testable predictions for exoplanet observations.
More about the research
This project models what that drifting recipe means for the planets themselves, asking how a rocky world born early in cosmic history differs from one born today.
Why it matters
Thousands of exoplanets are now known, but interpreting their densities and compositions requires knowing what raw materials were available where and when they formed. This modeling framework could tell observers which planet types to expect around stars of different ages and chemistries, sharpening the search for worlds capable of supporting magnetic fields, plate tectonics, atmospheres and ultimately life.
Known grants
From NIH and NSF research grants. Labs often have other funding we can't see.
Closest labs
Keith Hawkins
University of Texas at Austin, TX·Astronomy & Astrophysics
Measure phosphorus abundances in stars across two distinct cosmic environments, the Milky Way and the accreted Gaia Enceladus dwarf galaxy, using astronomical spectroscopic observations, to constrain how much bulk phosphorus planets can inherit.
David Weinberg
Ohio State University, OH·Astronomy & Astrophysics
Measure how much core-collapse supernovae, Type Ia supernovae and asymptotic giant branch stars contribute to element abundance patterns, by modeling data from large spectroscopic surveys of Milky Way stars.
Eve Lee
University of California-San Diego, CA·Astronomy & Astrophysics
Separate the effects of dust-gas coupling, the Stokes number (St), from gas turbulence, the effective viscosity (alpha), by applying the dust equation of motion to a large sample of protoplanetary disks with rings.
The school
University of Nevada-Las Vegas: 4 labs on PI Pages, $118M a year on research, 241 research doctorates a year.
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