what’s new

Astronomers have observed a binary star system orbiting near the supermassive black hole at the center of the Milky Way galaxy.

The discovery of Sagittarius A* (Sgr A*), published on Tuesday in The nature of communicationis the first confirmed case of two stars gravitationally bound together so close to a black hole.

Why it matters

The environment surrounding supermassive black holes like Sgr A*—which is 4 million solar masses—was thought to be too turbulent for binary star systems to survive.

The discovery of D9 challenges this long-held belief and suggests that these regions may be more stable than previously thought. “This is great news,” said Florian Peissker, lead author of the study and an astrophysicist at the University of Cologne.

He added that their discovery was serendipitous: “We’re actually in a really lucky situation. We observed the system just in time.”

What to know

The binary stars, known as D9, are estimated to be only 2.7 million years old – remarkably young by cosmic standards – and are in the narrow survival zone. The further apart, the enormous gravitational force of the black hole would tear them apart; the closer, the stars would merge into one.

“That leaves some questions still open,” said Anna Ciurlo, an astrophysicist at the University of California, Los Angeles, who was not involved in the study.

Using the Very Large Telescope (VLT) in Chile’s Atacama Desert, astronomers detected and measured the high velocities of D9 stars. At first, the team believed they had found a single star, but further analysis revealed it was a binary pair.

The stars reside in the S cluster, a group of high-velocity stellar bodies that orbit Sgr A* under its immense gravity. The D9 system provides new insight into the nature of these regions where stars can exist despite the influence of a black hole.

The discovery also sheds light on “G objects” in the S-cluster – mysterious entities that look like clouds of gas and dust but behave like stars. Some scientists speculate that these objects may be remnants of previous binary mergers, suggesting that D9 could offer insight into their origins.

What people are saying

Florian Peissker, lead author at the University of Cologne: “Our discovery allows us to speculate about the presence of planets, as they often form around young stars. It seems likely that the detection of planets in the galactic center is only a matter of time.”

Emma Bordier, researcher at the University of Cologne: “This provides only a brief window on cosmic timelines to observe such a binary system – – and we succeeded!”

Michal Zajaček, astrophysicist at Masaryk University: “The D9 system shows clear signs of gas and dust around the stars, suggesting that it could be a very young star system that must have formed near a supermassive black hole.”

What happens next

Astronomers plan to use upgrades to the VLT and the upcoming Extremely Large Telescope (ELT) to take a closer look at D9 and other objects in the S-cluster.

These instruments can also help confirm whether conditions near Sgr A* can allow the formation of planets around young stars like those in the D9 system.

The nature of G objects and the evolution of binaries in extreme gravitational fields remain lingering questions, but discoveries like D9 are bringing astronomers closer to understanding how stars can exist—and thrive—near the heart of our galaxy.

This article contains reports from The Associated Press