April 7, 2026
Will blend atmospheric observations and theory to reveal the nature of sub-Neptunes, the galaxy's most common worlds
The Heising-Simons Foundation announced Caroline Piaulet-Ghorayeb as a recipient of the 51 Pegasi b Fellowship. With a PhD in Physics from the University of Montreal and currently a Margaret Burbidge Prize Postdoctoral Fellow in Astronomy and Astrophysics, Piaulet-Ghorayeb is among eight fellows selected for 2026.
When the JWST began returning its first exoplanet observations, Caroline Piaulet-Ghorayeb was part of the global team ready to interpret them. After weeks of preparation, she downloaded the telescope’s first real measurements and ran them through the analysis pipeline she had built. Slowly, a spectrum appeared on her screen—the atmosphere of a distant planet traced in delicate molecular lines. For the first time, astronomers could glimpse chemical footprints of a world far beyond our solar system in striking detail.
Moments like this sit at the heart of Piaulet-Ghorayeb’s work. She studies the atmospheres of planets orbiting other stars, combining telescope observations with theoretical modeling to turn raw data into a tangible story about the planet behind it.
“What I like most about exoplanetary science is the discovery aspect,” said Piaulet-Ghorayeb. “You’re the first to look at the data—extracting what matters, making sense of the observation, and telling the story of what it means.”
Her research has already led to several important discoveries. She identified the first steam world atmosphere on GJ 9827 d—a small planet shrouded with water vapor. “Understanding where water exists in planetary systems is a steppingstone toward both identifying habitable environments and understanding the processes that shape the smallest planets we can characterize in detail today,” she said.
Piaulet-Ghorayeb later led a landmark study of TRAPPIST-1 d, a rocky planet in its star’s habitable zone, showing that it likely lacks a thick Earth-like atmosphere—an important step in narrowing the search for habitable worlds. In another study, she helped redefine the nature of WASP-107 b, a giant super-puff planet with exceptionally low density, showing that it likely formed far from its star before migrating inward. Along the way, she has developed a widely used library of open-source tools that help astronomers isolate planetary signals from starlight and model what lies beneath the atmosphere.
Beyond research, she is deeply committed to mentoring the next generation of scientists. She founded InitiaSciences, a Canadian nonprofit dedicated to scientific outreach for underrepresented and socioeconomically disadvantaged youth, creating hands-on opportunities to help students explore their own spark for science.
“It’s important for young people to see themselves in researchers,” she said, “to ask questions, be curious, and imagine themselves doing this work.”
As a 51 Pegasi b Fellow, Piaulet-Ghorayeb will focus on one of the biggest mysteries in planetary science: sub-Neptunes. These planets—larger than Earth but smaller than Neptune—are the most common worlds in the galaxy, yet their compositions remain unclear. Building on her discovery of GJ 9827 d’s atmosphere, she will combine new observations with advanced modeling to understand how clouds and hazes obscure atmospheric signals, what those atmospheres reveal about planetary interiors, and where water-rich sub-Neptunes originate. Her work aims to illuminate how the galaxy’s most common planets form and evolve—and what they may reveal about potentially habitable worlds.
About the 51 Pegasi b Fellowship
The 51 Pegasi b Fellowship provides early-career postdoctoral scientists the opportunity to lead transformative research in planetary astronomy. Each year, up to eight fellows with outstanding potential receive three-year, $468,000 grants to pursue novel theoretical, observational, or experimental studies. These fellowships enhance our fundamental understanding of the Solar System, exoplanets, and the celestial processes that shape planetary systems. After completing the fellowship, fellows may apply for an additional year of funding to continue their postdoctoral work or support them if they receive a faculty position.
This fellowship is part of the Science Program’s commitment to supporting scientific advancements in astronomy and cosmology that illuminate our basic understanding of the universe, its celestial objects, and processes.
Learn more about the fellowship and the fellows.