Light in the Sky Caused by Star ‘Squeezed’ by Black Hole
According to astronomers, a “extraordinary flash” seen in the sky earlier this year was caused by a distant star being “squeezed like a toothpaste tube” by a supermassive black hole (see artist’s impression of a star being ‘squeezed’ by a black hole above)
When the star got too close to the black hole, it emitted a light show brighter than a thousand trillion suns. The tidal disruption event (TDE), which occurs when a star is ripped apart by the tidal forces of a black hole, was bright enough to be detected by instruments on Earth.
Although TDEs have been seen before, experts say this one, called AT2022cmc is the brightest yet!
It is also the most distant TDE ever detected, at more than eight billion light-years away, more than halfway across the universe.
The researchers believe their findings, which were published in the journals Nature and Nature Astronomy, could help explain how supermassive black holes feed and grow.
“We know there is one supermassive black hole per galaxy, and they formed very quickly in the universe’s first million years,” said Dr Matteo Lucchini, a postdoc researcher at the MIT Kavli Institute for Astrophysics and Space Research in the United States and one of the authors on the Nature Astronomy paper.
Dr Daniel Perley, a reader in astrophysics at Liverpool John Moores University and one of the Nature paper’s authors, described AT2022cmc as an “extraordinary” type of TDE.
“The most known types of explosions are either much faster, much slower, or much bluer in colour than data suggests,” he said.
“In most cases, intense gravitational forces tear the star apart… However, in this case, something happened that ejected matter back into space at nearly the speed of light. We describe it as a toothpaste tube being suddenly squeezed in the middle, causing the contents to squirt matter out of both ends.”
The remnants of the squeezed star created a powerful jet, resulting in what scientists call a “extraordinary flash” detected during a routine all-sky survey in February at the Zwicky Transient Facility in California.
Experts believe the luminous jet was pointing directly at Earth, allowing instruments and telescopes to capture the event in great detail.
TDEs like AT2022cmc are rare, according to astronomers; the last time one of these jets was discovered was more than ten years ago.
Multiple instruments from around the world were used to learn more about the event, including the Liverpool Telescope in Spain and the European Southern Observatory’s Very Large Telescope in Chile.
According to astronomers, AT2022cmc was hot – around 30,000 degrees – which is typical for a TDE.
However, it remains unknown why some TDEs launch jets while others do not.
Astronomers believe that as more powerful telescopes are launched, they will be able to observe more TDEs and get some answers.
