In October 2018, astronomers saw a black hole 665 million light-years from Earth burst into light as it ripped apart a small star. However, 3 years later, the black hole illuminated the universe again when no new objects were observed. Astronomers pointed out that the explosion came from a star that was swallowed 3 years ago, but somehow delayed for several years and ejected material. No one has seen this. kind of thing.
According to the Department of Physics of Tsinghua University, when an unfortunate star is too close to the black hole at the center of the galaxy, the strong tidal force generated by gravity will tear the star apart. This catastrophic event is called a tidal disruption event. TDE). During the swallowing process, about half of the stellar debris swirls into the black hole through the accretion circle, producing a dazzling light that illuminates the entire galaxy; in some cases, the black hole also emits a stream of particles traveling close to the speed of light.
Harvard-Smithsonian Center for Astrophysics (CfA) astronomer Yvette Cendes’ team re-examined the tidal disruption events that have occurred in the past few years, and did not expect to find the first wave of 2018 in radio data from the Very Large Array (VLA). The AT2018hyz event that emerged has once again seen an unusual outburst.
At that time, scientists used visible light telescopes to find that a star was torn and devoured by a black hole 665 million light-years away from the earth. The theoretical model calculated that the mass of the star was only one-tenth of the sun, and the material spit out after the black hole tore the celestial body was produced. A tidal disruption event that disappeared after months of monitoring under visible light.
However, after three years, the black hole suddenly ejected a pile of matter at a speed of up to half the speed of light. This is the first time astronomers have witnessed a black hole eating and spitting out for such a long time.
At present, scientists do not know why black holes delay the ejection of matter for many years. The team hopes to further explore whether this kind of thing happens frequently in other black holes, and also hope to learn more about the feeding behavior of black holes.
The new paper is published in The Astrophysical Journal.
(Source: Harvard-Smithsonian Center for Astrophysics)
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