Bigger star clusters do not hang around in their dusty cradles for long. New observations from the James Webb Space Telescope and the Hubble Space Telescope show that the most massive star clusters clear away the gas clouds they are born in much faster than smaller ones do. Once those clouds are gone, the clusters flood their galaxies with ultraviolet light, affecting how and where other stars and planets can form.
Four galaxies under the microscope
An international team of astronomers studied thousands of young star clusters in four nearby galaxies: Messier 51, Messier 83, NGC 4449, and NGC 628. The researchers used Webb’s infrared eyes to peer through the dense gas that hides the youngest clusters, while Hubble provided sharp visible light images of more mature clusters. By comparing clusters at different stages of evolution, the team could see how quickly each one had blown away its natal cloud.
What stellar feedback means for galaxies
Stars are born when clouds of gas collapse under their own gravity. As a cluster forms, its most massive stars produce powerful winds, intense ultraviolet radiation, and eventually supernova explosions. These forces push the surrounding gas away, ending further star formation in that cloud. This process, known as stellar feedback, means that most of the gas in a galaxy never gets used to make stars. The new results show that the more massive the cluster, the sooner it finishes this job and starts shining freely into its galaxy.
Why local astronomers care
Studying star clusters in the Milky Way and its dwarf satellite galaxies gives scientists a close up view of individual stars. But our position inside the Milky Way’s disc blocks the view of many star forming regions. Observing nearby galaxies with space telescopes lets astronomers survey entire populations of clusters at once. The FEAST observing programme, which collected the data for this study, was designed to fill that gap. The findings help explain how star formation works on a galactic scale and how the timing of a cluster’s emergence affects the environment where planets might later form.
The study was published in a peer reviewed journal and relied on data from both Webb and Hubble. By combining their strengths, astronomers now have a clearer timeline of how star clusters evolve from hidden embryos into bright sources of ultraviolet light that shape their host galaxies.
