Extraordinary Trinary Black Hole System Is the First of Its Kind Ever Found

A Unique Discovery in Cygnus Constellation

In the constellation Cygnus, about 7,800 light-years from Earth, lies a true cosmic oddity: the V404 Cygni system, home to a black hole known for its intriguing and unpredictable behavior. Recently, this system revealed yet another surprise to scientists—a hidden binary companion, a star in a wide orbit that takes approximately 70,000 years to complete.

Since V404 Cygni already has a nearby companion star that completes its orbit every 6.5 days, the discovery of this third object turns the system into a “trinary” configuration. This is the first time we’ve seen such a setup, and it could help clarify how black holes form, as current theories suggest that a supernova explosion—the process by which stellar-mass black holes are thought to originate—would normally destroy the fragile gravitational connection of such a distant orbit.

“We think most black holes form from violent explosions of stars, but this discovery makes us question that theory,” says Kevin Burdge, a physicist at MIT.

“This system is an incredible discovery for black hole evolution, and it also raises the possibility that there are other similar triple systems out there.”

Evidence for a Triple System

In fact, we’ve known about the second star in the V404 Cygni system for decades; until now, astronomers thought it was simply a nearby star with no direct link to the black hole. However, data from the Gaia mission, by the European Space Agency, which maps the position, direction, and speed of objects in the Milky Way, indicated something more complex.

V404 Cygni and the supposedly unrelated star are moving in the same direction and at the same speed, suggesting a gravitational connection between them.

“This is not a coincidence,” says Burdge. We observe two stars moving together because a weak gravitational force links them, forming a triple system.

Such evidence supports the theory that black holes form from supernova explosions, the giant eruptions of dying stars that release the outer material while the core collapses to form a black hole. However, some black holes may also form through a process called direct collapse, where the massive star implodes completely, without a violent explosion.

In this direct collapse model, there’s little evidence to observe because there are no residues characteristic of supernovae. This is precisely where V404 Cygni becomes particularly interesting—if a supernova explosion occurs asymmetrically, the unequal energy creates a “push” for the newly formed black hole.

The Challenge of Wide Orbit and Gravitational Connection

However, the large distance between the black hole and the newly discovered star—approximately 3,500 astronomical units—makes it difficult to reconcile this idea with their weak gravitational connection. A supernova would likely have easily broken this link.

The wide orbital separation also makes it challenging to explain this configuration through gravitational capture between two passing objects. After conducting thousands of simulations, Burdge and his team concluded that the most plausible explanation is that the three objects were already gravitationally bound when the black hole formed and that the formation mechanism involved direct collapse.

Our simulations show that the most viable way for this triple system to exist is through direct collapse,” says Burdge.

This discovery provides the best evidence so far for the direct collapse model in black hole formation, strengthening this theory as a valid explanation for cases where a supernova does not explain a black hole’s origin.

There could be other triple systems, with black holes in wide orbits, that we have not yet detected due to the stealthy nature of these objects. Finding more systems like this could help us understand how black holes form and why, in some cases, they collapse directly instead of exploding in a supernova.

Either we got very lucky, or ternary systems are common,” says Caltech astronomer Kareem El-Badry.

“If they are common, this could answer long-standing questions about how black hole binaries form. Triples create evolutionary pathways that are not possible for pure binaries.”

It’s been suggested before that black hole pairs may form mostly through the evolution of triples, but direct evidence was lacking until now.”

Read the original article on: Science Alert

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