A team of astronomers has detailed how star clusters use gas from the galaxies housing them to produce their own new stars.
Published in the journal Nature, the new study details how globular clusters may not form in one giant burst, but over time by gradually churning out new stars.
"In a star cluster, the first stellar generation usually contains very massive stars, and those very massive stars will contribute very high-energy photons - that is, X-ray photons - into their environment," study lead author Chengyuan Li, an astronomer at Peking University, told Space.com. "A cluster is initially gas-rich, but after that first batch of massive stars pours their energetic photons out, most of the gas will get accelerated and escape from the cluster. About 3 million to 10 million years later, the star cluster will be gas-free, hence quenching the star-forming process."
Scientists previously found globular clusters at least 10 billion years old that had many relatively young stars, but the new study seeks to uncover how this happens. For their research, the astronomers used Hubble data on three globular clusters in two dwarf galaxies.
"Our explanation that secondary stellar populations originate from gas accreted from the clusters' environments is the strongest alternative idea put forward to date," study co-author Richard de Grijs, an astronomer at KIAA and Chengyuan's Ph.D. advisor, said in a press release. "Globular clusters have turned out to be much more complex than we once thought.
"We have now finally shown that this idea of clusters forming new stars with accreted gas might actually work, and not just for the three clusters we observed for this study, but possibly for a whole slew of them."
