Astronomers are watching two unusual black holes, each presenting phenomena that challenge current understanding of these cosmic giants. One, a “serial killer” black hole, is about to devour its second star within five years, while the other, part of the newly discovered triple system V404 Cygni, has disrupted long-held theories of black hole formation.

The Black Hole “Serial Killer” Reaches for Another Star

Located 215 million light-years from Earth, this supermassive black hole first caught scientists’ attention five years ago with a bright flare. The flare came from a star that had drifted too close to it, sparking what astronomers call a tidal disruption event, or AT1910qix. Gravitational forces stretched and tore apart the star, leaving part of its remains around the black hole and launching the rest into space.

Led by Dr Matt Nicholl of Queen’s University Belfast, a team of astronomers has tracked this remnant disc over several years using high-powered telescopes such as the Chandra X-ray Observatory and the Hubble Space Telescope. Recently, another star has started passing through this disc every 48 hours, creating bright X-ray bursts with each collision. Dr Nicholl describes it as similar to a diver creating splashes in a pool each time they hit the water, with the star as the diver and the disc as the pool.

“What’s uncertain is what will ultimately happen to this star,” Dr Nicholl said. “It could be pulled into the black hole, or it may eventually disintegrate from these repeated impacts.”

A Rare Triple Black Hole System in Cygnus

Meanwhile, in the constellation Cygnus, a rare triple system is raising questions about black hole origins. Known as V404 Cygni, this system includes a nine-solar-mass black hole and two orbiting stars, one much farther away than astronomers had thought possible. Kevin Burdge, an MIT research fellow, notes that a supernova typically pushes any distant companions too far to remain gravitationally bound. But in this system, a distant star orbits at a staggering 300 billion miles.

In their Nature paper, Dr Burdge and his team proposed that this black hole may have formed without a supernova explosion, possibly “quietly” collapsing without ejecting its nearby companions. This hypothesis has sparked interest among scientists, as it hints at new black hole formation processes yet to be fully understood.

Daniel Holz, an astrophysicist at the University of Chicago, noted that while unlikely, nature often defies assumptions. This discovery could open a new chapter in black hole research.

 

Astronomers traditionally believe black holes form when massive stars explode in supernovas, creating objects so dense that their gravitational force prevents even light from escaping. However, recent evidence suggests some black holes may also form without such explosive events.
Scientists have discovered a black hole that likely formed when a large star’s core collapsed without the typical explosion. This black hole exists in a unique arrangement, gravitationally connected to two regular stars.
While binary systems containing a black hole paired with another star or black hole are known, this discovery represents the first confirmed triple system comprising a black hole and two stars.
Located in the Cygnus constellation approximately 7,800 light-years from Earth, this system features V404 Cygni, a black hole initially thought to have only one stellar companion. Data from the Gaia space observatory revealed its second companion.
The black hole, approximately nine times more massive than our sun, is currently drawing material from its closest companion star, which has 0.7 solar masses and orbits every 6-1/2 days at a distance one-seventh that between Earth and the sun.
This nearby star has expanded into a red giant phase, allowing the black hole to extract its material. A second star, 1.2 times the sun’s mass, orbits the pair every 70,000 years at a distance 3,500 times greater than Earth’s solar distance.
The system’s stability suggests the black hole formed without an explosion, as a supernova would have disrupted the triple arrangement. This supports the “direct collapse” theory, where stars implode after depleting their fuel without an explosive event.