Astronomers have found an incredible new galaxy very far away. Specifically, they provided the first observational confirmation that a star had survived such a catastrophic near-miss with a supermassive black hole and returned for a second pass. What an exceptional occurrence in a galaxy with a black hole containing millions to billions of times the mass of our sun. With this remarkable discovery, scientists now have a wonderful opportunity to dive deeper into the nature of cosmic phenomena.
In its first meeting, the star was only partially torn apart. At least that half of its mass was “swallowed” up by the black hole, while the rest was ejected violently in the opposite direction. This dramatic interaction generated a flare that captivated observers for several weeks to months, offering astronomers a rare opportunity to study the properties of the black hole involved.
Dr. Lydia Makrygianni from Lancaster University in the UK supervised by Prof. Iair Arcavi at Tel Aviv University’s Astrophysics Department. What their research uncovered was nothing short of amazing, for not only did the star survive its close shave with danger—it passed through a similar galactic gauntlet two years later! That redundancy ignited a second flare that closely resembled the first. It implies these disasters were examples of muting disruption rather than total catastrophe.
Such a rare and important discovery would not have been possible without the detection of the double tidal disruption event named AT 2022dbl. The researchers looked closely at the flares that erupted during these flybys. Their aim was to have a better understanding of how stars interact with supermassive black holes.
“The question now is whether we’ll see a third flare after two more years, in early 2026,” – Prof. Iair Arcavi
The implications of their findings are significant. The first and second flares were eerily similar. This indicates that we might need to rethink our picture of tidal disruptions on the stellar end.
“If we see a third flare,” continues Arcavi, “it means that the second one was also the partial disruption of the star. So maybe all such flares, which we have been trying to understand for a decade now as full stellar disruptions, are not what we thought.” – Prof. Iair Arcavi
The researchers refer to these flares as “snacks” that the supermassive black hole gulps down. Farther afield, the discovery represents a seismic challenge to our long-held beliefs about the nature of these cosmic tangoes.
“Either way,” adds Arcavi, “we’ll have to re-write our interpretation of these flares and what they can teach us about the monsters lying in the centers of galaxies.” – Prof. Iair Arcavi