UK-led study uncovers hidden star clusters deep inside nearby galaxies

PASADENA, Calif. (June 17, 2026) — A University of Kentucky researcher is helping uncover how stars are born and evolve deep inside galaxies — by revealing dozens of previously hidden star clusters buried in cosmic dust. 

Using a combination of NASA’s James Webb Space Telescope (JWST) and radio observatories including the Atacama Large Millimeter/submillimeter Array (ALMA) and the Karl G. Jansky Very Large Array (VLA), the study provides new insight into how galaxies build their stellar populations over time.

The findings from “Hidden Gems in the Hearts of Nearby Galaxies: Evolution of Young Massive Star Clusters in Circumnuclear Rings” were presented today at the 248th meeting of the American Astronomical Society (AAS) in Pasadena, California.

Sajia Shahrin Neha, a predoctoral researcher in the UK Department of Physics and Astronomy, led the new analyses that expand earlier work on galaxy NGC 3351 and introduces a second galaxy, NGC 1097, to better understand how young star clusters form and evolve. 

“These young, massive clusters are extreme star-forming regions in the earliest stages of their lives. They are still in the natal clouds of cosmic gas and dust,” Neha said. “Unfortunately, the same cosmic dust obstructs our view, especially in the optical wavelength.”

By combining observations across multiple wavelengths — from radio to infrared — the research team identified compact young massive clusters hidden within dense, dusty rings at the centers of both galaxies. Radio observations from ALMA and the VLA allowed researchers to see through dust that blocks optical telescopes, while JWST independently confirmed the clusters and revealed surrounding structures of gas and dust. 

The team detected roughly 50 young star clusters spanning all stages of early development — from deeply embedded protoclusters to more evolved systems. Building on earlier work, the research also maps a timeline of how these clusters form and evolve over time, offering one of the clearest pictures yet of their early lifecycle. 

“We found that these massive star clusters form over an extended period of time, longer than what we would expect based on typical star forming regions in the present-day universe,” Neha said. “In the end, they use up most of their gas reservoir to give birth to new stars, making them extremely efficient stellar nurseries.”

The work builds on previous research led by Neha’s advisor, UK astrophysicist Jiayi Sun, Ph.D., whose team studies how gas and stars interact to regulate star formation and drive galaxy evolution. 

“Neha’s work highlights the latest breakthroughs from a large, coordinated team effort,” Sun said. “We are drawn to the universe’s most extreme star-forming environments because they push our best theories to their limits. And because such conditions were once common in the early universe, this research opens a rare window into cosmic history, allowing us to glimpse the distant past in our own cosmic backyard.” 

“This work weaves together several important themes in modern astrophysics, from the birth of stars to the inner workings of galaxies and their evolution across cosmic time,” said Eva Schinnerer, Ph.D., senior group leader at Max Planck Institute for Astronomy and a key collaborator on the project. “It also underscores the power of combining ground- and space-based telescopes, showing how different wavelengths of light reveal complementary parts of the same cosmic story.”

The 248th AAS meeting runs through June 18 at the Pasadena Convention Center. Learn more at aas.org/meetings/aas248.