Distant black hole spotted annihilating a star

Astronomers have detected an act of extreme violence being committed on the other side of the known universe, with a black hole destroying a star that got too close to this celestial savage. But this was no ordinary case of a hungry black hole.

According to scientists, it was 1 of just 4 examples — and the first since 2011 — of a black hole observed in the process of ripping apart a passing star, in a so-called tidal disruption event, and then spewing out luminous jets of particles. energy waves in opposite directions in space. And it was the most distant and also the most luminous event of its kind ever recorded.

Astronomers described the event in studies published on Wednesday (30) in the scientific journals Nature and Nature Astronomy.

The “culprit” appears to be a supermassive black hole that would have a mass hundreds of millions of times greater than that of our Sun, located about 8.5 billion light years away from Earth. A light year is the distance traveled by light in one year: 9.5 trillion kilometers.

“We thought the star was similar to our Sun, possibly more massive, but of an ordinary type,” 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 detected in February by the astronomical probe Zwicky Transient Facility, using a camera attached to a telescope at the Palomar Observatory in California. The distance was calculated using the Very Large Telescope at the European Southern Observatory 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 force, something similar to the way the Moon pulls the tides on Earth. , but with greater force,” said Michael Coughlin, an astronomer at the University of Minnesota and a co-author of the study.

“Next, pieces of the star are caught in a disk that rotates at high speed and orbits the black hole. Finally, the black hole consumes what’s left of the destroyed star in the disk. In some very rare cases, which we estimate to be a hundred times more rare, strong jets of material are thrown in opposite directions when the tidal disruption event occurs,” added Coughlin.

Andreoni and Coughlin said the black hole is likely spinning at high speed. This may help explain how the two powerful jets were launched into space at nearly the speed of light.

Astronomer Dheeraj Pasham of the Massachusetts Institute of Technology and lead author of the other study said the researchers were able to observe the event very early on – less than a week after the black hole began consuming the doomed star.

Researchers detect tidal disturbance events about twice a month, but tidal disturbance events that produce jets are extremely rare. One of the jets emanating from this black hole appears to be pointed towards Earth, so it appears brighter than if it were directed in the other direction. It is an effect known as “Doppler boosting”, similar to the heightened sound of a police siren as it passes by the observer.

The supermassive black hole is thought to reside at the center of a galaxy, in much the same way that the Milky Way and most galaxies have such a black hole at their core. But the tidal disruption event was so bright that it obscured the galaxy’s starlight.

“At its peak, the fountain looked brighter than a thousand trillion suns,” Pasham said.