It has been observed that a black hole that devours a star with strong gravity ejects part of the star over time. The photo is an imaginary depiction of a black hole spewing out stellar debris. /Getty Image Bank
Research has shown that a black hole that swallows a star spews out the star’s debris like burps several years later.
As a result of observing black holes for a long time, a joint research team from Harvard University and the Smithsonian Center in the United States confirmed that 10 out of 24 black holes emit radio waves of explosive intensity 2 to 6 years after attracting stars by tidal forces. The results of this study were recently published on Archive, an online paper publication site.
The ‘black hole burp’ was observed after the ‘tidal destruction phenomenon’ occurred, in which a black hole attracts and destroys stars passing by. When a star gets closer than the tidal radius, which is the range affected by the black hole, it is destroyed by the tidal force of the black hole and about half of the star’s mass is slowly sucked into the black hole. Remnants of stars that are sucked into a black hole emit strong light around the black hole, and by observing this, scientists learn that a tidal disruption phenomenon has occurred. Since the first observation in 1990, astronomers have observed about 100 tidal disruption events.
Dr. Sendis’s research team discovered a strange phenomenon while continuously observing the black hole where this tidal destruction phenomenon occurred. Several years after the tidal destruction event, the black hole spit out part of the star it had swallowed. Usually, after discovering a tidal disruption phenomenon, scientists no longer observe the same black hole. Since observation equipment is limited, there is no need to wait for the same phenomenon again. Dr. Sendis, who led the research, said, “We started observing again to see what happened at the site of the explosion. Then, after the tidal disruption phenomenon ended, we observed a phenomenon that seemed to suddenly turn on radio waves from a black hole that had not been emitting radio waves. “It’s done,” he said. The researchers said, “As a result of observing 25 black holes that have experienced tidal disruption, we confirmed that this phenomenon occurs in 10 of them,” adding, “However, we do not yet know why this phenomenon occurs.” The research team nicknamed this phenomenon ‘black hole trim.’ This is because there is a time lag between the star being sucked into the black hole and the broken parts being ejected.
However, just because the name is ‘Trim’, it is difficult to say that the material inside the black hole actually came out. The gravity of a black hole is so great that not even light can leak out. The researchers said, “We do not yet know whether the powerful radio waves we observed came from the remnants of stars left after being sucked into the black hole, or whether such energy was stored near the black hole.”
