A distant black hole is caught in the act of destroying a star
This artist’s impression illustrates what it might look like when a star gets too close to a black hole, where the star is squeezed by the black hole’s intense gravitational pull. Some of the star’s material is pulled in and swirls around the black hole, forming the disk that can be seen in this image. In rare cases, such as this one, jets of matter and radiation are shot out from the black hole’s poles. (ESO, M.Kornmesser via Reuters)
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WASHINGTON — Astronomers have detected an act of extreme violence more than halfway across the known universe as a black hole rips apart a star that wandered too close to this celestial savage. But this was no ordinary case of a predatory black hole.
It was one of only four examples — and the first since 2011 — of a black hole observed in the act of tearing apart a passing star in a so-called tidal disruption event and then shooting glowing jets of high-energy particles in opposite directions into space. the researchers said. And it was both the most distant and the brightest such event in history.
Astronomers described the event in studies published Wednesday in the journals Nature and Nature Astronomy.
The culprit appears to be a supermassive black hole, believed to be hundreds of millions of times the mass of our sun, located approximately 8.5 billion light-years from Earth. A light year is the distance light travels in one year, 5.9 trillion miles.
“We think the star was similar to our sun, maybe more massive, but of a general appearance,” said astronomer Igor Andreoni of the University of Maryland and NASA’s Goddard Space Flight Center, lead author of one of the studies.
The event was discovered in February by the Zwicky Transient Facility astronomical survey using a camera attached to a telescope at the Palomar Observatory in California. The distance was calculated using the European Southern Observatory’s Very Large Telescope in Chile.
“When a star gets dangerously close to a black hole – don’t worry, this won’t happen to the sun – it is violently torn apart by the black hole’s gravitational tidal forces – similar to how the moon pulls on Earth’s tides, but with a greater force,” said University of Minnesota astronomer and study co-author Michael Coughlin.
“Fragments of the star are then captured in a rapidly spinning disk orbiting the black hole. Finally, the black hole swallows up what remains of the doomed star in the disk. In some very rare cases, which we have calculated to be 100 times rarer, powerful jets of material are shot out in opposite directions when a tidal disruption occurs,” Coughlin added.
Andreoni and Coughlin said the black hole was likely spinning rapidly, which could help explain how the two powerful jets were shot into space at nearly the speed of light.
MIT astronomer Dheeraj Pasham, lead author of the other study, said the researchers were able to observe the event very early — within a week of the black hole beginning to swallow the doomed star.
While researchers detect tidal disturbance events about twice a month, those that produce jets are extremely rare. One of the jets emitting from this black hole appears to be pointing towards Earth, making it appear brighter than if it were heading in another direction – an effect called “Doppler amplification”, which is similar to the amplified sound of a passing police siren .
A supermassive black hole is thought to be at the center of a galaxy – just as the Milky Way and most galaxies have one at their core. But the tidal disruption event was so bright that it eclipsed the galaxy’s starlight.
“At its peak, the source appeared brighter than 1,000 trillion suns,” Paschamp said.
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