The Voracious Appetite of Black Holes

Black holes are known for their destructive nature when they come into contact with stars. These powerful cosmic entities can pull stars into their orbit, leading to a slow and painful death for the unfortunate star. A recent study utilizing X-ray data from Chandra and other instruments has shed light on a supermassive black hole in a distant galaxy that is slowly consuming a captured star. This ongoing event provides valuable insights into various physical processes in the universe.

The journey begins with the discovery of AT2018fyk, a “tidal disruption event” (TDE) observed back in 2018. Initially detected by NASA’s Neutron star Interior Composition Explorer (NICER), follow-up observations were conducted using Chandra and ESA’s X-ray telescope, XMM-Newton. Typically, a TDE marks the end of the story as the star gets consumed by the black hole, emitting intense X-rays and UV rays from a staggering distance of 860 million light years.

However, astronomers noticed another surge in X-ray and UV emissions from the same black hole approximately two years later. This spike indicated that the star, captured in a highly elliptical orbit, was being partially devoured again. The star’s close approach to the black hole resulted in the ripping away of more material, triggering another TDE. Scientists predicted the end of this feeding frenzy to be in August 2023 based on their calculations and requested observational time on Chandra. As anticipated, on August 14th, 2023, a significant decrease in emissions from the black hole was observed, signaling the possible complete demise of the star or its miraculous escape to continue its erratic orbital dance.

The star at the center of AT2018fyk may not have been alone in its cosmic journey. Researchers speculate that it belonged to a binary star system, with its partner star being ejected as they encountered the black hole’s gravitational pull. The expelled star is now racing away from the galaxy at high speed, potentially escaping its gravitational clutches. However, the fate of the remaining star remains uncertain, with questions arising about its future luminous burnoff events. Predictions suggest that the next surge in brightness could occur between May and August of 2025, lasting longer than previous occurrences.

The intriguing nature of the AT2018fyk system has attracted significant attention, offering a rare opportunity to study TDEs and test theoretical predictions. The research team is likely to seek additional observational time in the coming years to monitor any potential third feeding event of this captivating black hole. This ongoing saga serves as a reminder of the relentless and voracious appetite of black holes, shaping the fate of celestial bodies that come too close to their grasp.