In a discovery that has shaken up modern astrophysics, scientists at Tel Aviv University (TAU) and an international research team have for the first time recorded a rare phenomenon: a star that survived a "collision" with a supermassive black hole not once but twice.
This discovery, recently published in the prestigious journal The Astrophysical Journal Letters, describes a flare recorded almost identical to the phenomenon that occurred 2 years earlier, originating from the same location in the universe.
The flare occurred when a star named AT 2022dbl approached the black hole but was not completely swallowed as scientists had predicted.
“The star was not completely destroyed, but actually survived,” said Professor Iair Arcavi, lecturer in the Department of Astrophysics at TAU and Director of the Wise Observatory at Mizpe Ramon. “This is the first time we have seen a star come back in such a short time on a human scale.”
According to scientists, the star AT 2022dbl orbits the black hole in an elliptical orbit, similar to the Earth orbiting the Sun, with a period of about 700 days. When the star approaches the closest point in its orbit, part of it is pulled in by the black hole's extremely strong gravity.
“This second time, it is possible that the entire star was destroyed,” Professor Arcavi speculates. “We will only know for sure when we wait to see if this phenomenon occurs a third time in early 2026. It is possible that the flares that we have been thinking about as being caused by the destruction of the entire star, are not actually so.”
Astronomers have long known that the center of most galaxies contains a supermassive black hole, with a mass millions to billions of times that of the Sun.
These massive entities, including the black hole at the center of the Milky Way, have a major influence on the formation and evolution of the entire galaxy.
A black hole is a region of gravity so strong that not even light can escape.
One of the few observational methods to study them is through tidal disruption events, when a star is torn apart by gravity as it approaches a black hole. The destroyed star’s material is sucked into the black hole, heating it to extremely high temperatures and creating a powerful flare.
Such events offer scientists a brief but valuable window into the mysterious nature of black holes. But in fact, many of the flares observed over the past decade have been dimmer and cooler than theoretical predictions.
Scientists say the center of the galaxy is extremely crowded and dense with stars, in contrast to the "suburbs" where humans on Earth live.
According to Professor Arcavi, in the center is a very bustling and chaotic area, there is a supermassive black hole and there are many things that humans do not yet understand.
Astronomers now know that when a massive star ends its life and collapses, it can become a black hole with a mass about 10 times that of the Sun.
“We used to think that stars being completely torn apart in the centre of galaxies meant the complete disappearance of the star,” said Professor Arcavi. “But now we have found a star that has only been partially destroyed, which helps explain many mysteries and opens the door to a better understanding of black holes.”
Source: https://www.vietnamplus.vn/lan-dau-tien-ghi-nhan-ngo-sao-song-sot-sau-2-lan-va-cham-voi-ho-den-khong-lo-post1051117.vnp
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