Supermassive Black Hole 9 Billion Light-Years Away Consumes Largest Star Ever Observed
TL;DR
Version is their collaborator discovered a black hole that shredded a star (called a Tidal Disruption Event (TDE)) that was initially misclassified as a supernova and occurred about 9 billion light years away, well beyond where they normally see these things. It looks like it was insanely bright like this thanks to a star 9x the mass of our star getting shredded, which is many times bigger than what we have seen before in terms of stellar mass.
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Astronomers have identified a black hole engaging in an extraordinary cosmic feast about 9 billion light-years away from Earth.
This supermassive black hole, with a mass roughly 10 million times that of the Sun, was caught devouring a star nine times as massive as our own. This event marks the largest star ever observed being consumed in a “tidal disruption event” or “TDE.”
To put it in perspective, this star (named AT2023vto) is five times the size of the next biggest stellar body ever seen being destroyed by a black hole, making AT2023vto the largest and brightest TDE ever recorded.
However, this is not the most distant TDE ever observed.
The difference with those more distant TDEs is that they release jets of material moving at nearly the speed of light, making them incredibly bright and easier to detect at great distances. AT2023vto, like most TDEs (about 99%), does not currently exhibit these so-called relativistic jets — though that could change.
“This is the furthest of this nonrelativistic category of TDEs seen thus far. That’s for sure,” said Cendes. “Studying this is going to be very important for understanding what happens when more mass is thrown into a black hole.”
Epic cosmic feast
TDEs occur when a star’s path brings it dangerously close to a supermassive black hole. The black hole’s massive gravitational pull causes intense tidal forces that stretch the star vertically while compressing it horizontally, hence the term “tidal disruption event.”
“What sets the TDE AT2023vto apart from others is how incredibly bright it is,” explained Yvette Cendes from the University of Oregon. “It’s located 9 billion light-years away, which is extremely distant, but it’s so luminous that we can still observe it. Typically, TDEs are found much closer to us.”
The star is then drawn out into a long thread of plasma in a process dramatically referred to as “spaghettification.”
“TDEs are fascinating because they offer a unique physical lab where we can test things that we can’t replicate on Earth,” Cendes said. “Since we can’t create black holes on Earth to experiment with, studying the variations between TDEs is always going to be exciting.”
The actual TDE itself lasts only a few hours, and the black hole consumes only a small fraction of the star.
“When a TDE occurs, only a small part of the star’s mass actually falls into the black hole,” Cendes said. “About half the star’s mass is ejected into space, never to return. The rest forms an accretion disk around the black hole.”
As a result, the supermassive black holes involved in TDEs go from occasionally feeding on gas or dust, remaining relatively quiet, to being at the center of a chaotic, luminous environment, allowing them to be observed across vast cosmic distances. Cendes noted that before the black hole at the heart of AT2023vto devoured this star, its surrounding area wasn’t visible from 9 billion light-years away.
AT2023vto was first detected by the Zwicky Transient Facility (ZTF), appearing as a sudden flash of light. Initially, it was misclassified as a Type II supernova, an explosion caused by a massive star collapsing under its gravity.
Cendes explained that this confusion was cleared up by Harsh Kumar, a researcher at the Center for Astrophysics (CfA) Harvard & Smithsonian. By analyzing the ZTF data and modeling the light curve, Kumar was able to determine the true nature of AT2023vto, including the masses of the black hole and the star and its distance.
Cendes and the team then used the Very Large Telescope (VLT) to search for any radio emissions from AT2023vto but found none.
“We didn’t detect anything, which might seem less exciting, but it helps to rule out possibilities,” Cendes said. “For instance, if black holes produce relativistic jets in TDEs, which are extremely bright, we usually observe radio emissions. Since we didn’t detect any, we can rule out the possibility of relativistic jets here.”
However, Cendes hasn’t dismissed the idea that this supermassive black hole could eventually “burp” out a relativistic jet. She was part of a team that observed another black hole producing powerful jets years after consuming a star. The reason for such a delayed reaction remains a mystery even two years later.
Cendes is keen to observe whether the black hole at the center of AT2023vto will display similar behavior.
“This is still an ongoing event; the light is still there. We’re going to keep studying it,” Cendes said. “I’m certainly curious to see if this one will eventually produce a black hole burp. Just because we haven’t detected radio emissions yet doesn’t mean there won’t be any later on.”
“I find this particularly intriguing since it seems to be a common phenomenon that lacks a clear explanation. There’s a lot about TDEs that we still don’t fully understand.”
A pre-peer-reviewed version of the team’s research is published on the paper repository arXiv.
