For the first time, researchers have spotted a binary star — a system of two stars that orbit each other — near the Sagittarius A* (Sgr A*) supermassive black hole at the center of our galaxy. Binary stars have been observed elsewhere in the universe as a common occurrence, but never in the vicinity of a supermassive black hole.
The pair of stars, dubbed D9, was revealed from data collected by the European Southern Observatory’s Very Large Telescope (VLT) in Chile. Presented in a new Nature Communications study, the discovery of D9 has proved that binary stars can briefly endure the extreme gravitational forces generated by black holes with substantial proportions like Sgr A*.
“Black holes are not as destructive as we thought,” said Florian Peißker, lead author of the new study and a researcher at the University of Cologne, Germany, in a statement.
A Resilient Binary Star
Normally, the gravitational pull imposed by a supermassive black hole would tear apart stars that reach too close, prompting a tidal disruption event. Here, stars undergo spaghettification; though this process may not exactly sound threatening, it marks the demise of a star, which is vertically stretched as the black hole devours it. Meanwhile, debris is collected near the black hole and starts to swirl around it, forming into a bright, superheated accretion disc.
However, as the new study reveals, some binary stars can survive in these conditions, albeit only for a brief amount of time. It appears that researchers caught D9 at just the right moment — the binary is estimated to be 2.7 million years old (very young for a star system), and within one million years, it will likely merge into a single star due to gravitational forces.
Previously, scientists thought stars were unable to form near supermassive black holes, but this notion was reversed when collections of young stars were found in close proximity to Sgr A*. Now, D9 adds to the idea that star systems are capable of existing near supermassive black holes and brings into question the environments of these black holes.
Read More: Astronomers Found a Baffling Black Hole That Existed 13 Billion Years Ago
What Surrounds a Supermassive Black Hole?
D9 was found in a cluster of stars and other objects orbiting Sgr A* called the S cluster. Researchers are working to decipher oddities within this cluster called G objects, which behave like stars but look like clouds of gas and dust. While studying the surrounding objects of Sgr A*, they found that D9 was two stars orbiting each other.
This discovery may help researchers determine true identity of the G objects. They say these objects could be a combination of binary stars that have not yet merged and leftover material from stars that have already merged.
The origins of the objects surrounding Sgr A* are still up in the air — researchers are primarily concerned with how they could form so close to the supermassive black hole. Sgr A* previously made headlines in 2022 and earlier in 2024 when it was captured in images that displayed its swirling magnetic fields.
Efforts to study the supermassive black hole and nearby objects will soon be bolstered by the GRAVITY+ upgrade to the VLT Interferometer and the METIS instrument on the Extremely Large Telescope, an upcoming observatory under construction in Chile. For now, the results shown with D9 hold exciting possibilities for the future of research on stars — and maybe even planets — near supermassive black holes
“Our discovery lets us speculate about the presence of planets, since these are often formed around young stars. It seems plausible that the detection of planets in the Galactic center is just a matter of time,” said Peißker.
Read More: Black Holes Eat Far More Voraciously Than We Previously Thought, and They Make a Mess
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Jack Knudson is an assistant editor at Discover with a strong interest in environmental science and history. Before joining Discover in 2023, he studied journalism at the Scripps College of Communication at Ohio University and previously interned at Recycling Today magazine.
