In a galactic drama unfolding 665 million light-years away, a star met its demise in October 2018 by venturing too close to a supermassive black hole, succumbing to a tidal disruption event (TDE). While TDEs are not uncommon, the aftermath of this stellar tragedy took an unprecedented turn three years later.
In June 2021, astronomers observed the same black hole illuminating the cosmos once again, not by consuming a new celestial victim, but by expelling material at an astonishing speed. This peculiar event, detailed in a study published in the Astrophysical Journal on Oct. 11, has left scientists bewildered.
The typical scenario after a star meets its fate near a black hole involves violent spirals and a flash of observable energy. Yet, in this case, the black hole surprised researchers by ejecting material at 50 percent the speed of light, resembling a sudden “burp” of stellar remains from a meal consumed years prior.
Yvette Cendes, a research associate at the Center for Astrophysics (CfA), expressed the astonishment, stating, “It’s as if this black hole has started abruptly burping out a bunch of material from the star it ate years ago.”
The unexpected outflow not only defies conventional expectations but also ranks among the most radio luminous TDEs ever witnessed. The mystery deepens as scientists grapple with the question of why the black hole unleashed this delayed cosmic encore years after the initial feast.
While theories are still in the nascent stages, researchers are contemplating whether similar delayed outbursts are more common than previously recognized. By utilizing the Very Large Array, astronomers have initiated a search for additional late-stage TDEs. A preliminary detection involving a TDE named AT2019teq has already been announced, displaying a delayed outflow growing brighter since September 2022. Further observations will be crucial to confirming this finding.
Should late-stage TDEs become a prevalent phenomenon, it offers scientists an intriguing new dimension to probe the enigmatic nature of black holes. Yvette Cendes emphasizes the significance, stating, “It would mean we have an entirely new regime to study black hole physics that we didn’t have before! Since we can’t test the extreme physics around them on Earth, having a new window into their behavior off Earth is always exciting.” The cosmic encore of black hole burps unveils a captivating chapter in the ongoing quest to understand the profound mysteries of our universe.
