Infrared observations using the ERIS instrument show that four dusty objects near Sagittarius A* continue to move in stable orbits. The findings strengthen the possibility that G2 is not a free gas cloud, but a star enveloped in dust, and show that even a binary star system can survive near a supermassive black hole.
In the heart The Milky Way, located about 26 thousand light years from Earth, Sagittarius A* – The supermassive black hole, which has a mass about four million times greater than the mass of the Sun. Stars, gas clouds, and mysterious dusty bodies move rapidly around it, in an environment where gravity is strong and the density of stars is extremely high.
For years, astronomers have predicted that at least some of the dusty objects in the region will stretch, break apart, and eventually be swallowed by the black hole. But more precise observations show that the reality is not so simple: four objects that have been examined continue to move in orderly orbits, without the dramatic signs of destruction predicted in some models.
The study was led by Dr. Florian Peisser from the University of Cologne. The team used ERIS, an enhanced resolution imaging and spectroscopy instrument installed on the European Southern Observatory’s Very Large Telescope (VLT) in Chile. ERIS observes in the near infrared and allows researchers to discern objects hidden behind the abundant dust at the center of the galaxy. The study was published in late 2025 in the journal Astronomy & Astrophysics.
G2 didn't behave like a normal cloud
The most famous of the four is G2, also known as DSO. When it was discovered, it appeared to be a compact source of gas and dust orbiting very close to Sagittarius A*. Researchers assumed it was a cloud that contained no stars, so they expected the black hole's tidal forces to stretch it into an elongated shape and tear it apart.
Such a process is sometimes called “spaghettification,” but the more accurate term is tidal elongation: the side closer to the black hole is pulled more strongly than the far side, and the difference between the forces stretches the body.
G2 reached its closest approach to the black hole in 2014. Ahead of the event, astronomers expected a significant breakup of the cloud and an increase in Sagittarius A* activity, as gas fell towards it. In fact, G2 remained much more compact than expected and there was no dramatic outburst that could be attributed to its ingestion. Previous studies have already raised the possibility that a star is hiding within the dust envelope. ([arXiv][2])
The new ERIS observations support this explanation. G2's location and motion are consistent with the Kepler orbit calculated for it, and there is no sign that it has become a free stream of gas being swallowed by the black hole. According to the researchers, this behavior is more consistent with a compact stellar body surrounded by gas and dust than with a free cloud.
A Keplerian orbit does not mean that the object is not affected by the black hole. On the contrary: the orbit is determined primarily by the gravity of Sagittarius A*. The finding means that the object remains bound and intact enough to orbit the black hole, rather than scattering and disappearing.
A star couple who survived where they didn't expect to find couples
The object D9 provides another example. In 2024, Feisker and colleagues reported that D9 is not a single star but a binary system—two stars orbiting each other and simultaneously moving around Sagittarius A*. This was the first binary system confirmed so close to a supermassive black hole.
The researchers detected the binary through periodic changes in radial velocity – the source’s motion towards and away from us, measured by the shift of lines in the spectrum. The two stars complete one orbit around each other every 372 days. Their estimated masses are about 2.8 and 0.73 solar masses.
The distance between the two components of the system is small enough for their mutual gravitational pull to overcome the difference in the black hole's gravitational pull between the two stars. According to the study, the semi-major axis of the inner orbit is about 1.59 astronomical units, much smaller than the calculated tidal disruption radius of the system, about 42 astronomical units. Therefore, the black hole is unable to immediately break up the pair. ([Nature][4])
However, “stable” is not necessarily “eternal.” D9 is very young in astronomical terms—it is estimated to be about 2.7 million years old—and the cumulative influence of the black hole could gradually alter the inner orbits of the stars. The researchers estimate that they could merge into a single star within about a million years.
X3 and X7 also continue on their paths
The team also examined X3 and X7, dusty objects with different characteristics that reside in the dense and dynamic environment of the galactic center.
X3 is thought to be a young, massive stellar object surrounded by matter, forming a bow shock-like structure in front of it due to its motion relative to the surrounding gas. ERIS observations have shown that it continues to move along its expected trajectory, although acceleration in its motion has been measured. ([arXiv][5])
X7 is a more elongated object, which also has a shock-wave-like structure in front of it. Previous studies have suggested that the black hole's tidal forces are stretching it and that it will eventually break apart. The new observation found no clear evidence that the head of the structure is getting significantly closer to Sagittarius A*. According to the researchers, X7 continues to move north along its orbit, and its behavior is not necessarily consistent with a scenario of an immediate fall into the black hole.
The measurements do not prove that the objects are immune to change. They show that over the observed timescale, their orbits are more stable and their structures more durable than some early predictions suggested.
Why doesn't the black hole "eat" everything?
A black hole doesn't automatically suck everything in its vicinity in. A body can continue to orbit it for a long time, just as the Earth orbits the Sun, as long as it has the right speed and trajectory and doesn't get too close to the limit where tidal forces pull it apart.
The ability to survive depends on the distance from the black hole, the size of the body, and the degree of internal confinement. A diffuse gas cloud is more vulnerable than a dense star. A wide binary system is more vulnerable than a pair of stars moving in a tight orbit. Therefore, two bodies in the same region can respond completely differently to the gravity of Sagittarius A*.
The new findings do not make the center of the galaxy a calm environment. Stars there move at speeds of thousands of kilometers per second, intense radiation and stellar winds fill the region, and gravitational encounters can change orbits and cause mergers. But they show that even in this environment, compact bodies and young systems can persist for hundreds of thousands or even millions of years.
Are G-selfs the products of stellar mergers?
The identity of “Self G"The center of the galaxy is still not agreed upon. They appear in some observations as clouds of dust and gas, but move in orbits more similar to those of stars. D9 provides a possible clue to the solution: some of the objects may be binary systems about to merge, while others are stars that formed after the two components merged and remained enveloped in gas and dust.
The researchers also raise the possibility that the dynamical processes near the black hole not only break up systems, but may also encourage mergers that create larger stars and unusual dusty bodies. This is still a hypothesis that needs further observations, and not proof that the black hole itself is creating stars.
Future monitoring using ERIS, the GRAVITY+ upgrade, and the Extremely Large Telescope, ELT, being built in Chile, is expected to allow astronomers to measure the motion of objects with greater precision, track changes in shape, and determine which of them are stars, binary systems, or products of mergers.
“The fact that these objects are moving so steadily so close to a black hole is fascinating,” said Feisker. He said the results show that Sagittarius A* is less destructive than previously thought, making the center of the galaxy a natural laboratory for studying the interactions between stars and black holes.
For the original publication: Opening the original publication
Questions and Answers
Why doesn't Sagittarius A* swallow all the objects in its vicinity?
A black hole does not automatically suck in every nearby object. Stars and other objects can orbit it in stable orbits as long as their speed and distance are appropriate. Only an object that gets too close, or whose structure is not tightly bound, can be torn apart by tidal forces or fall into the black hole.
What is G2, and why did it surprise astronomers?
G2 initially appeared as a cloud of gas and dust, so it was expected that the gravity of Sagittarius A* would stretch and collapse it as it approached the black hole. In fact, it remained relatively compact and continued on its orbit. This behavior strengthens the possibility that a star is hidden within the dust envelope.
How does the binary star system D9 manage to survive near the black hole?
The two stars in D9 orbit each other in a tight orbit, so their mutual gravity is strong enough to counteract the tidal forces of Sagittarius A*. However, the influence of the black hole may gradually change their orbits and eventually lead to their merging into a single star.
Do the findings prove that the center of the galaxy is a safe environment for stars?
No. The center of the Milky Way is still an extreme environment with strong gravity, radiation, stellar winds, and frequent collisions between objects. The findings just show that not every object near the black hole is destroyed immediately, and that some stars and star systems can survive there for longer than expected.
More on the subject on the science website
- Does the mysterious glow at the center of the Milky Way actually come from dark matter?
- Euclid Space Telescope Maps 60 Million Stars in the Dense Heart of the Milky Way
- The Milky Way was rebuilt in an ancient collision and is already entering a new galactic dance with the Large Magellanic Cloud.
- Supermassive black holes could harm the chances of life even at great distances
- A double star near the black hole at the center of the Milky Way may be feeding it small gas clouds
