UF astronomers use James Webb Space Telescope to uncover hidden stars in the Milky Way’s largest stellar nursery

Astronomers at the University of Florida are using the world’s most powerful telescope to reveal secrets of the largest star-forming cloud in our galaxy.

Using the James Webb Space Telescope, UF researcher Nazar Budaiev, along with Associate Professor of Astronomy Adam Ginsburg, Ph.D., and an international team of astronomers, captured the first detailed views of Sagittarius B2, a massive cloud of gas and dust near the center of the Milky Way. Often called a “stellar nursery,” Sgr B2 is the most active birthplace of stars in our galaxy.

What the astronomers saw was unexpected, and the images opened an entirely new window into the cloud’s hidden complexity.

For the first time, scientists saw stars that had been completely invisible until now, their light buried beneath layers of gas and dust. JWST’s powerful infrared instruments also captured light slipping through the dense cloud, following narrow tunnels carved by stellar winds and outflows. These “escape routes” offer astronomers an unprecedented glimpse into how massive star clusters take shape.

“This cloud produces the most stars of any structure in the Milky Way, yet JWST is showing us we may have underestimated how active it truly is,” Budaiev said. “In almost every way this is a brand-new look into this part of the galaxy.”

The new observations also revealed a striking asymmetry in the cloud itself. While much of Sagittarius B2 is turbulent and irregular, one side ends in a sharp, straight edge that according to Ginsburg hints that there has been a compression event that crushed the cloud.

Because conditions inside Sgr B2 resemble those in distant galaxies from billions of years ago, the study provides an important window into how stars and star clusters formed in the early universe.

“This discovery shows the power of Webb to uncover the unseen,” said Ginsburg. “It’s not just giving us a clearer picture of our own galaxy, but also helping us understand how galaxies grew and evolved across cosmic time.”