Emily Chan
After watching a giant black hole consume a nearby star, astronomers have been able to successfully forecast when it takes its meals, bringing them a step closer to understanding the behavior of colossal black holes.
In 2018, a ground-based survey observed a surge in brightness from a galaxy that was about 860 million light-years away from Earth. The event was triggered by a supermassive black hole from a faraway galaxy shredding and consuming a star.
As the star’s mangled material approached the black hole, it heated up and blasted X-ray and ultraviolet emissions that were strong enough for space telescopes to detect. A little over a year later, the signals faded, suggesting that the black hole had completely devoured the star.
Then, two years later, the signals appeared again, showing that the star’s core actually survived while its outer cores were demolished.
Based on this data, along with telescope data about the star and its orbit, a team of researchers created a model to predict that the black hole’s second meal would end in August 2023. The results were confirmed with follow-up observations taken by the Chandra X-ray Telescope.
“The telltale sign of this stellar snack ending would be a sudden drop in the X-rays, and that’s exactly what we see in our Chandra observations on Aug. 14, 2023,” Dheeraj Pasham, the leader of the new study from the Massachusetts Institute of Technology. “Our data show that in August last year, the black hole was essentially wiping its mouth and pushing back from the table.”
The star that would serve as the black hole’s meal had a companion star, which was tossed into space at a speed of 621 miles per second, according to Muryel Guolo, a co-author of the study from John Hopkins University in Baltimore.
“The doomed star was forced to make a drastic change in companions—from another star to a giant black hole,” said Guolo. “Its stellar partner escaped, but it did not.”
Ultimately, the star was polished off in multiple small portions, which was unconventional behavior of a black hole.
Sign up for Chip Chick’s newsletter and get stories like this delivered to your inbox.
