The Black Hole Catcher project is online! LAMOST discovers the largest constant-star black hole to date

Technology 1Years ago (2020) mobodigital
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November 28, 2019, nature, the world's leading scientific journal, published a major discovery led by astronomers in China online. A team led by researchers Liu Jifeng and Zhang Wei of the National Observatory of the Chinese Academy of Sciences has discovered the largest stellar-scale black hole to date, a supermassive star-level black hole 70 times the mass of the sun that is well beyond the upper limit predicted by theory, upending the perception of stellar-level black hole formation and driving the revolution in stellar evolution and black hole formation theory.

, cosmic absorbers

Hawking wrote in his final book, "Ten Questions," "Facts are sometimes more wonderful than fiction, and black holes are the most authentic, and they are more wonderful than anything a science fiction writer imagines." In 1915 Einstein proposed general relativity, and German physicist Karl Swasey deduled a precise solution to Einstein's field equation, foreshadowing the existence of black holes. Since then, mankind has not stopped imagining and exploring this mysterious object.

1965, Spector X-1 became the first black hole candidate to be discovered due to its strong X-ray radiation; In 2019, astronomers used eight observation points on four continents over a 10-year period to capture visual evidence of a black hole -- the first black hole "Fangrong", edgy affinity for the once "invisible" object. What exactly is a black hole and why has it fascinated generations of astronomers? It doesn't glow in itself, it's very dense (compressing a star 10 times the mass of the sun into a sphere the size of a beijing six-ring, which is the same density as a black hole), and it's super attractive, and any material passing by it, even the fastest light, can't escape, and this magical object is a black hole. Therefore, it can be said that black holes are veritable cosmic vacuum "absorbers".

astronomers have divided black holes into star-level black holes (100 times the mass of the sun), medium-mass black holes (100 times to 100,000 times the mass of the sun) and supermassive black holes (more than 100,000 times the mass of the sun), depending on the mass of the black hole. Star-level black holes are formed by the death of large-mass stars and are widely known as "residents" of the universe. A star evolves to the end If the remaining mass is too much (greater than three times the mass of the sun) to form neither a white dwarf nor a neutrogen star, once it enters the stage of death, there is no force to prevent the star from continuing to collapse under the ultimate gravitational force, eventually forming a dense black hole. There may be a medium-mass black hole at the center of esqueer clusters and dwarf galaxies, while there are supermassive black holes at the center of galaxies, such as a supermassive black hole about 4 million times the mass of the sun at the center of the Milky Way.

, how to observe the formation of star-level

mysterious and interesting black hole, if dragons dive into the abyss, hidden claws, sneaking in the cosmic sea of stars. If a black hole forms a dense 2-star system with a normal star, it will reveal its jaws and, with a powerful "taste", sucks the gas from the star's companion star directly, forming a suction disk that emits bright X-rays (Figure 1). These X-ray rays, like the "backlight" before these substances were swallowed up by black holes, are a powerful clue that astronomers have been searching for signs of black holes over the years. Astronomers then measure the mass of black holes by monitoring the motion of companion stars, which can be applied to black hole systems that are bright companion stars. Another approach is for rare double black holes, in which scientists listen mainly to the ripples of space-time through gravitational waves experiments, which in turn infer the black hole's co-occurring events.

so far, almost all star-level black holes in the Milky Way have been identified by X-rays emitted by the black hole's absorption of companion gas. Over the past 50 years, about 20 black holes have been discovered in this way, all between three and 20 times the mass of the sun.

There are hundreds of billions of stars in the Milky Way, and according to the theory, there should be hundreds of millions of star-level black holes in the Milky Way that have died of mass, and only a fraction of the X-ray radiation that can be emitted in the black hole's twin system. When a black hole is far away from its companion stars, our "big stomach king" also shows a calm and gentle side, so how do we search for these flat static (non-absorbent companion gas) black holes? Astronomers have given a new answer to the discovery of the largest star-level black hole.


image of a black hole sucking up X-rays (from the network) of the

, capture the "hidden" black hole

team led by the National Observatory found an unusually large 2-star system in the vast sea of stars, which could contain a hidden black hole. More than 700 days of pursuit of the road full of hardships and wonderful.

In early 2016, researcher Zhang Wei, director of the LAMOST Scientific Patrol Department, and Han Zhanwen, a member of the Yunnan Observatory, proposed a two-year spectral monitoring of more than 3,000 objects in a Sky Zone (K2-0) in Kepler to conduct a two-year research project using LAMOST to observe the 2-star spectrum. Among them is a "walking wind" B star that caught the attention of researchers, showing regular periodic motion and unusual spectral characteristics.

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