Ohio State astronomy professor awarded Henry Draper Medal

COLUMBUS, Ohio – Adam Leroy, a professor of astronomy at The Ohio State University, has been named the recipient of the 2025 Henry Draper Medal. 

The oldest medal awarded by the National Academy of Sciences, the Henry Draper Medal celebrates those who have made “a recent, original investigation in astronomical physics, of sufficient importance and benefit to science to merit such recognition.” It is awarded every four years.

Leroy’s work was selected for pathbreaking efforts that have characterized, “in unprecedented detail, the physical nature of the interstellar medium and its relationship to star formation in nearby galaxies.” 

“We are thrilled that the National Academy of Sciences has recognized Professor Leroy with the Henry Draper Medal,” said David Horn, dean of the College of Arts and Sciences at Ohio State. 

“His pioneering contributions have advanced our understanding of the composition and history of the universe, and this prestigious award further enhances the reputation of our outstanding Department of Astronomy.”

The interstellar medium that Leroy studies is the gas and dust between stars. This material fills the space in galaxies, and often contains primordial leftovers from the beginnings of the universe. Because it is the fuel from which future stars are born and a complex ecosystem that links past and future generations of stars, the interstellar medium is a crucial research target for many fields of astronomy.  

“Understanding how cosmic ecosystems evolve is a big topic in astronomy right now,” Leroy said. “Because of technology made available to us in only the last five to 10 years, we’ve been able to bring this topic into focus, making new observations that finally answer questions we’ve had for decades.

Using special telescopes to study all sorts of light, especially radio and infrared light, allows scientists to peer into the interstellar medium directly, said Leroy. Before coming to Ohio State, Leroy worked at the National Radio Astronomy Observatory, which operates the Atacama Large Millimeter/submillimeter Array (ALMA) and Very Large Array (VLA) Radio Telescope facilities. 

It was there that he began harnessing cutting-edge technology to conduct studies on molecular gas and star formation in galaxies. This led to him co-founding the PHANGS-ALMA project, now widely recognized as the first systematic survey of the many stellar nurseries and galaxies that dot our sky. 

“Lots of people do surveys of one galaxy or a small part of our Milky Way using one type of light and get a ton of detail, but miss the big picture,” said Leroy. “With PHANGS, we have worked to line up all the best telescopes in the world on a representative set of galaxies in order to take pictures of the entire cosmic ecosystem.” 

While scientists in the past could only obtain blurred or indistinct pictures of the gas and dust in faraway galaxies, today these same structures can be seen with remarkable detail.  

By combining the ALMA radio array with powerful instruments like the Hubble Space Telescope and the James Webb Space Telescope, the PHANGS-ALMA project has mapped the gas, dust and newly born stars for more than 100,000 stellar nurseries across nearly 100 galaxies, providing a new generation of astrophysicists with an in-depth view of the area where stars and planets form. 

“What we’ve done is build an observational basis that informs how we go from a cosmos full of just spread-out hydrogen gas to the cosmos full of stars and galaxies we see around us,” Leroy said. “Our observations get at the core physics behind how galaxies turn their gas into stars.”

Many previous recipients of the Henry Draper Medal have a record of continued achievements in their fields: Six recipients have been honored with a National Medal of Science, while nine recipients have gone on to win the Nobel Prize in Physics.

“This medal feels very validating for the impact of this work that our team has done,” Leroy said. “Studying the interstellar medium and star formation is important to many fields, but sometimes it can be under-the-hood research. So it’s neat to see it catching people’s imagination at the same level as black holes and pulsars.” 

Recipients also receive a cash prize of $25,000, which Leroy plans to use to bolster further collaboration with international colleagues, including other members of the PHANGS-ALMA team. Leroy praised the collaborative and supportive scientific environment at Ohio State for helping him win the award. 

“Ohio State’s astronomy department is world-famous for its invigorating, supportive atmosphere,” he said. “This is an amazing place to do cutting-edge research.” 

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Contact: Adam Leroy, [email protected] 

Written by: Tatyana Woodall, [email protected]