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Anna O’Grady Named NASA Hubble Fellow

Anna O’Grady didn’t just read The Illustrated Atlas of the Universe in eighth grade — she inhaled it. The images from the Hubble Space Telescope inside inspired her so strongly she says her “brain chemistry changed.” 

Now, the little girl who fell in love with those pictures is a 2026 NASA Hubble Fellow. 

O’Grady, currently a McWilliams Postdoctoral Fellow at ºÃÉ«ÏÈÉúTV's McWilliams Center for Cosmology and Astrophysics, has been awarded one of the 2026 NASA Hubble Fellowships, among the most prestigious and competitive postdoctoral fellowships in astrophysics. She is one of 24 fellows selected from more than 650 applicants. The fellowship supports exceptionally promising early-career astrophysicists whose work addresses some of NASA’s most fundamental questions about the universe. 

“When I think about the incredible work done by past Hubble Fellows, including many of my colleagues, I’m truly humbled. It’s a tremendous privilege to be counted among this group,” said O’Grady, who will continue her work as a Hubble Fellow at Carnegie Mellon. 

“Over the past three years at the McWilliams Center, it has been a pleasure to watch Anna develop an ambitious research program on massive binary stars and stellar populations in nearby galaxies, tackling fundamental questions about how massive stars evolve and end their lives. Her selection as a NASA Hubble Fellow — one of the most prestigious and competitive awards in astrophysics — is a well-deserved recognition of the importance of her work,” said Tiziana DiMatteo, professor of physics and director of Carnegie Mellon’s McWilliams Center for Cosmology and Astrophysics. 

“We are especially pleased that Anna has chosen to continue her research at Carnegie Mellon,” DiMatteo added. “With a Hubble Fellowship, she could have gone anywhere, and her decision to remain here reflects the strength of the scientific community we have built at the McWilliams Center. I look forward to seeing what she will accomplish in the years ahead.” 

O’Grady uses both ground- and space-based telescopes to study massive star pairs, or binaries. While some stars live solo, like our sun, most of the biggest stars in the universe have a companion. When the stars get close to each other, they can trade stellar material or even merge. These interactions play a major role in many areas of astrophysics, influencing everything from supernova explosions to the creation of gravitational waves. But scientists still don’t fully understand what happens during these stellar close encounters. 

O’Grady aims to change that. She studies yellow supergiant stars with companions in the Magellanic Clouds, two small galaxies orbiting the Milky Way. These satellite galaxies are perfect laboratories: close enough to see individual stars clearly, but distant enough to capture the entire galaxy as a whole. 

She’s built a catalog of hundreds of possible yellow supergiant binaries. When they’re in this phase, these stars get really big really fast, making them ideal for studying mass transfer — the moment when one star becomes so large that it starts giving material to its companion. 

“One of the big things we’re interested in is the physics around mass transfer,” O’Grady said. “The yellow supergiant phase is one of the prime areas where different types of mass transfer end up occurring, but yellow supergiant binaries have never been systematically studied as a population.” 

As a Hubble Fellow, O’Grady will dive deeper into the population of yellow supergiant binaries she’s identified in the Magellanic Clouds. Her goal is to understand how these yellow supergiant binaries interact and how those interactions influence each star’s life. She will use data from the Gaia space observatory to map the stars’ orbits, and spectroscopy to learn more about how they transfer mass and identify stars who have evolved into something interesting, like a helium giant, after interacting with their companion. 

Although she’s an observational astrophysicist, O’Grady also works closely with theorists like Carnegie Mellon Assistant Professor Katie Breivik, who created COSMIC, a tool that simulates huge populations of stars and tracks how they evolve, interact, merge, and explode. The partnership allows O’Grady to pair real-world observations with super powered simulations to answer some of the universe’s hardest questions. 

O’Grady joined the McWilliams Center for Cosmology and Astrophysics in 2023 after earning her Ph.D. from the University of Toronto and B.Sc. from Memorial University of Newfoundland and Labrador. 

“It’s an exceptional research environment, and I’ve genuinely enjoyed my time here. I’ve been especially impressed by the breadth of expertise, and I’m grateful to continue being part of this community,” O’Grady said.