Astronomers Accidentally Discover First Interstellar Trail of Stars
In a surprising twist, astronomers have stumbled upon the first-known intergalactic trail of stars, which suggests that more of these structures could be lurking in deep space, according to a new study.
Stellar streams are elongated threads of gravitationally entwined stars that have likely been torn away from their parent galaxies or nebulas by the gravitational pull of other nearby galaxies. While dozens of these streams have been mapped within galaxies, none had been discovered in intergalactic space, until now.
The study, published in the journal Astronomy & Astrophysics, reveals the first-ever intergalactic stellar stream, known as the Giant Coma Stream. This massive structure, around 10 times longer than the Milky Way, was found stretching through the Coma Cluster, a group of more than 1,000 small galaxies located about 321 million light-years from Earth.
The researchers initially stumbled upon the stellar stream while studying halos of dispersed stars around the Coma Cluster in an attempt to measure the dark matter that surrounds the galaxy group.
The team was surprised to find the fragile structure amid a hostile environment of mutually attracting and repelling galaxies. Normally, such a structure would be expected to be ripped apart by more massive galaxies, but the Giant Coma Stream has persisted and grown to its current size.
One possible explanation for the stream’s existence is dark matter, the elusive material they were originally looking for. While dark matter is effectively invisible and can only be detected through its gravitational interactions with visible matter, it is possible that dark matter within the galaxy group helped stretch the stellar stream into its current shape.
The discovery of the Giant Coma Stream opens the door for more intergalactic stellar streams to be found, and the researchers believe there could be many more out there. They hope that increasingly advanced telescopes, coupled with their findings, could help other astronomers find more of these stellar streams in the future.
The researchers are now planning to study the stream with more powerful telescopes to learn more about the mysterious structure and its origins. They also hope to analyze individual stars within the stream to see if they are unique in any way.