When stars get too close to supermassive black holes, they can be torn apart, creating brilliant flares that help scientists learn about these otherwise invisible giants and how matter behaves around them.
Over the past decade, a puzzling type of flare has emerged: bright in optical and ultraviolet light, yet not behaving as predicted. So researchers have been busy trying to figure out what’s going on.
Now, astronomers from Tel Aviv University have spotted something incredible. A star was seen flaring as it got shredded by a black hole, but shockingly, this happened two years after an almost identical flare from the same spot in space. That means the star survived the first encounter… and returned for round two!
This is the first confirmed case of a star coming back after a close call with a black hole. It challenges what we thought was possible and hints that tidal disruption events may be more complex and drawn out than we ever imagined.
Black hole eating stars, one after another
At the heart of every central galaxy, including our own Milky Way, lurks a supermassive black hole, millions to billions of times more massive than our Sun. While we know they exist (the one in our galaxy even earned a Nobel Prize for its discovery in 2020), how these cosmic beasts form or influence their galactic homes remains a mystery.
Why the struggle? Because black holes don’t emit light, they’re cosmic invisibles. Astronomers can only detect them by watching how nearby stars behave. That trick works for relatively close galaxies… but for distant ones, those motions are too faint to observe.
To crack this enigma, a team led by Dr. Lydia Makrygianni (now at Lancaster University) and Prof. Iair Arcavi from Tel Aviv University, joined by students and global collaborators, conducted new research published in The Astrophysical Journal Letters. Their work dives deeper into tidal disruption flares, flashes of light from stars torn apart by black holes.
Every so often, like once in 10,000 to 100,000 years, a star drifts a little too close to the supermassive black hole at its galaxy’s center. What happens next isn’t pretty: the star is torn apart in a violent display of gravity’s power. Half of its mass is devoured, the other half flung into space.
Supermassive black holes feasting on massive stars
As the star’s remains spiral into the black hole (picture water circling a drain), the material heats up dramatically, nearly reaching light-speed, and creates a glowing flare. This flare briefly illuminates the normally invisible black hole, providing astronomers with a rare opportunity to study its behavior.
But here’s the twist: the brightness and heat from these flares haven’t matched what models predicted.
For nearly a decade, scientists were stumped, until the flare named AT 2022dbl came along. This unusual event might be the long-awaited clue that helps unlock the true nature of these cosmic light shows.
A supermassive black hole may have nibbled on the same star twice, once in 2022 and again in 2024. Since the star seemed to survive the first encounter and returned, scientists now believe these dramatic cosmic flares might be the result of partial disruptions, rather than destruction.
A giant black hole tore apart a massive star
Prof. Arcavi wonders: If a third flare appears in 2026, could it mean the star has survived again? That would flip a decade of theories about these flares being one-time, star-ending events. On the other hand, if no flare comes, the second encounter might’ve finished the star off, which suggests partial and complete disruptions look deceptively similar.
Either way, this cosmic déjà vu is rewriting what we thought we knew about how black holes snack on stars, and how we study the mysterious beasts at the centers of galaxies.
Journal Reference:
- Lydia Makrygianni et al, The Double Tidal Disruption Event AT 2022dbl Implies that at Least Some “Standard” Optical Tidal Disruption Events Are Partial Disruptions, The Astrophysical Journal Letters (2025). DOI: 10.3847/2041-8213/ade155
