A Space Flash Detected in February Was a Black Hole Devouring an Unassuming Star
The bright light was the result of a rare cosmic occurrence known as a tidal disruption event
On February 11, a star approached a supermassive black hole and subsequently was shredded by the intense gravitational forces. From Earth, scientists observed the event as a distant flash of light.
Now, researchers have determined that the bright flash was the result of a tidal disruption event, a release of electromagnetic energy that occurs when a star wanders too close to a supermassive black hole and meets its fatal end, according to NASA.
At 8.5 billion light-years away from Earth, this was the farthest and brightest tidal disruption event ever discovered, according to a statement. Two studies published Wednesday in the journals Nature and Nature Astronomy detailed the rare cosmic event from earlier this year.
“When a star dangerously approaches a black hole—no worries, this will not happen to the sun—it is violently ripped apart by the black hole’s gravitational tidal forces—similar to how the moon pulls tides on Earth but with greater strength,” Michael Coughlin, co-author of the Nature study and astronomer at the University of Minnesota, tells Reuters’ Will Dunham.
During a tidal disruption event, the black hole tears the star into thin streams of matter in a process called “spaghettification.” As this happens, some of the star’s material enters the black hole, which releases of a jet of energy that’s so bright that it can be detected by astronomers, according to a 2020 release about a similar cosmic event.
The flash, named AT 2022cmc, appeared particularly bright. It was first detected by a telescope at the California Institute of Technology’s Palomar Observatory as part of the Zwicky Transient Facility astronomical survey. Then, the European Southern Observatory’s Very Large Telescope in Chile examined the event’s distance from Earth.
Researchers found that the black hole’s jet was pointed directly at our planet. This created a “Doppler-boosting” effect that made it appear brighter than if the jet were pointed elsewhere. AT 2022cmc is one of four detected instances of a star being swallowed by a black hole and the first tidal disruption event identified since 2011, according to the statement.
“The luminous jet of material was launched almost at the speed of light, and the jet was pointing in our direction,” Igor Andreoni, an astronomer at the University of Maryland and a co-author of the Nature paper, tells The Daily Beast’s Tony Ho Tran. “This is an extremely rare phenomenon, and it is even rarer that it can be observed at all, because the jet is collimated, which means that we can observe it only if we are very close to the direction in which it is pointing.”
Bright flashes observed in the sky are usually gamma-ray bursts, or quick blasts of high-energy gamma-ray light released when massive stars collapse, according to NASA. However, the researchers knew the February flare was too bright to have been a gamma-ray burst.
“As bright as [gamma-ray bursts] are, there is only so much light a collapsing star can produce,” Benjamin Gompertz, an astronomer at the University of Birmingham who led the gamma-ray burst comparison analysis, says in the statement. “Because AT 2022cmc was so bright and lasted so long, we knew that something truly gargantuan must be powering it—a supermassive black hole.”
Around the world, a total of 21 telescopes tuned to various wavelengths—including X-ray, radio and optical—observed the beam of light, reports Gizmodo’s Isaac Schultz. AT 2022cmc was the first Doppler-boosted tidal disruption event to be discovered using optical light.
With tidal disruption events being so rare, the researchers’ findings could provide new insight into the formation and development of supermassive black holes.
“Astronomy is changing rapidly,” Andreoni says in a statement. “Scientists can use AT 2022cmc as a model for what to look for and find more disruptive events from distant black holes.”