Black Hole Destroys Star in Galaxy Collision
- A team of astronomers has closely examined a rare and dramatic cosmic event: a star venturing too close to a supermassive black hole.
- These stellar encounters, occurring roughly 700 million light-years away in merging galaxies, result in the star being shredded and consumed by the black hole.
- The host galaxy, SDSSJ232323.79+104107.7, is merging with a galaxy at least ten times larger.This is only the second time a TDE has been observed in interacting galaxies, despite...
Star Torn Apart by Black Hole in merging Galaxies: A Rare Tidal Disruption event
Updated June 02, 2025
A team of astronomers has closely examined a rare and dramatic cosmic event: a star venturing too close to a supermassive black hole. This tidal disruption event (TDE), dubbed AT 2022wtn, offers insights into how such events influence the evolution of galaxies.
These stellar encounters, occurring roughly 700 million light-years away in merging galaxies, result in the star being shredded and consumed by the black hole. The resulting burst of light, brighter than the combined light of all stars in the host galaxy, alerts scientists to the star’s demise.
The host galaxy, SDSSJ232323.79+104107.7, is merging with a galaxy at least ten times larger.This is only the second time a TDE has been observed in interacting galaxies, despite theories suggesting that galaxy mergers create conditions favorable for these events.
(Image credit: Legacy Surveys / D. Lang (Perimeter Institute) / INAF / F. Onori)
AT 2022wtn was initially detected by the Zwicky Transient Facility (ZTF). further investigation revealed that the black hole has a mass approximately 1 million times that of the sun, and the devoured star was a low-mass star. However, this cosmic cannibalism event exhibits unique characteristics.
“It is indeed a peculiar event. Its light curve is characterized by a plateau in the phase of maximum brightness, lasting about 30 days, accompanied by a sharp drop in temperature and a spectral sequence that shows the progress of two emission lines corresponding to the wavelengths of helium and nitrogen,” said Francesca Onori, team leader at the National Institute for Astrophysics (INAF). “Somthing that we had never observed with such clarity.”
(Image credit: Legacy Surveys / D. Lang (Perimeter Institute) / INAF / F. Onori)
The process begins when a star’s orbit brings it too close to the supermassive black hole. The black hole’s gravity creates immense tidal forces, stretching the star into a “spaghettified” shape.
Some of the stellar debris forms a whirling accretion disk around the black hole, while a meaningful portion is ejected as powerful outflows. In AT 2022wtn, these outflows caused a radiant radio emission and extreme changes in the velocity of light-emitting elements.
(Credit image: ESA/C. Carreau)
The event also created an expanding spherical “bubble” of expelled gas, indicating the star’s complete destruction.
“We found clear traces of the dynamics of the surrounding material also in some emission lines which show characteristics compatible with a fast propagation towards the outside,” Onori said. “Thanks to our monitoring campaign, we were able to propose an interpretation of the origin of the observed radiation: AT2022wtn gave rise to a rapid formation of the disk around the black hole and the subsequent expulsion of part of the stellar matter.”
“This result is notably relevant, since the source of visible light and the physical conditions of the region from which it comes, in TDEs, are still under study,” Onori added.
What’s next
Further research into AT 2022wtn and similar tidal disruption events promises to shed more light on the complex interplay between black holes and their host galaxies, particularly in the context of galaxy mergers.