Stars are usually very “social” things. Thanks to gravity, they are often found bound together in full-fledged galaxies like our own Milky Way or much smaller star clusters.
But the ones spread throughout the universe are frauds stars which remain gravitationally unbound to the others, wandering endlessly in infinite space. Although the light from these stars, which is known as intracluster light, was first detected in 1951 by Fritz Zwicky, a new infrared study by Hubble Space Telescope shed light, if you’ll excuse the pun, on this faint glow – and the study could help scientists unravel the mystery of the origins of these wayward stars.
The study examined 10 galaxy clusters, or gravitationally bound groups of galaxies, at distances of up to 10 billion light years. What the researchers found in the data was that the ratio of the intracluster light compared to the total light of the clusters was constant. This suggests that the wandering stars are old – billions of years old – and probably not recently ejected from established galaxy clusters by stripping (when massive gravitational tides pull material from galaxies). If stripping were the main source of wayward stars, scientists would expect to see the fraction of intracluster light increase over time compared to the light of galaxy clusters.
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“We don’t know exactly what made them homeless. Current theories cannot explain our results, but somehow they were produced in large quantities in the early universe,” James Gee, an astronomer at Yonsei University in South Korea and co-author of the new research. it said in a statement. “In their early formative years, galaxies may have been quite small and shed stars quite easily due to weaker gravitational pull.”
While Hubble will continue to explore the universe looking for intracluster light, James Webb Space Telescope It is also getting into the fun. Together, the powerful observatories will hopefully help scientists unravel the mystery of how wandering stars are born.
And perhaps an even bigger mystery, as these strange stars can give scientists insight into dark matterthe invisible material that makes up most of the matter in the universe and whose gravitational force holds galaxies together.
“If we understand the origin of intracluster stars, it will help us understand the assembly history of an entire galaxy cluster, and they can serve as visible markers of the dark matter surrounding the cluster,” co-author Hyungjin Joo, also of Yonsei University, said in the same statement.
A report on the team’s research was published Wednesday (Jan. 4) in the journal Nature (opens in new tab).
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