Chasing the distant mysterious object in the vast universe, countless scientists have been on the move for hundreds of years. In the early hours of November 28, Chinese scientists announced that, relying on China’s independently developed Guo Shoujing telescope LAMOST, the success of “live capture” a “king of the black hole.” This has upended the perception of the formation of star-level black holes and is expected to revolutionize the theory of stellar evolution and black hole formation , with the mystery of the universe being unveiled to the world.
“Facts are sometimes more wonderful than fiction, and black holes are the most realistic, more wonderful than anything sci-fi writers think. Hawking wrote in his final book, Ten Questions.
Through the unremitting efforts of scientists, in the early hours of November 28, Chinese scientists announced: relying on China’s self-developed Guo Shoujing telescope LAMOST, the success of “live capture” a “king of a black hole” – the milky galaxy found in the star-level black hole, the size of the sun 70 times the size, about 15,000 light-years away from us.
The “little king” black hole in a star-class black hole is of a mass greater than scientists think. “This is an extraordinary discovery that will force astronomers to rewrite models of the formation of star-level black holes. Experts said.
Cosmic light absorbers
In 1915, Einstein proposed general relativity, and German physicist Carl Schwarzsi oedd out an accurate solution to Einstein’s field equation, predicting the existence of black holes. Since then, mankind has not stopped imagining and exploring this mysterious object. Gravitational waves detected for the first time in 2015 providemore concrete evidence of the existence of black holes. This year, astronomers spent 10 years capturing visual evidence of black holes, the first black hole, “fangs”, using eight observation points on four continents, giving the once “invisible and untouchable” object a touch of affinity.
What exactly is a black hole, and why have generations of astronomers been so fascinated? It doesn’t glow, it’s super-attractive, anything passing by it, even the fastest light can’t escape – a black hole, a veritable cosmic vacuum “light absorber.” Not only that, it’s surprisingly dense. How big is it? Compressing a star 10 times the mass of the sun into a sphere the size of a six-ring edi-ring in Beijing is equivalent to the density of a black hole.
Depending on the mass of the black hole, astronomers divide black holes into star-level black holes (100 times below the mass of the sun), medium-mass black holes (100 times to 100,000 times solar mass) and supermassive black holes (100,000 times solar mass). Star-level black holes are formed by the death of large-mass stars and are the “inhabitants” of the universe.
According to scientists, a star evolved to the end if the remaining mass is too much, that is, more than three times the mass of the sun, it can not form a white dwarf star, nor can it become a neutron star, once into the stage of death, there is no force to prevent the star under the ultimate force of gravity continued to collapse, eventually forming a dense black hole.
“The center of globular clusters and dwarf galaxies may have medium-mass black holes, but there are supermassive black holes at the center of galaxies, such as a supermassive black hole at the center of the Milky Way that is about 4 million times the mass of the sun. Liu Jifeng, a researcher at the National Observatory, said.
“Capture” black holes
Mysterious and interesting, if the dragon dives into the abyss to hide its teeth and sneak into the universe’ sea of stars. But black holes themselves do not glow, how do astronomers find them in the vast universe?
The answer is indirect observation. Liu Jifeng said that observational and verification of black holes usually have two methods, one is through gravitational wave experiments to listen to the ripples of space-time, and then to fersatthe the black hole conjuncting events, but this only applies to the rare double black hole, that is, two galaxies colliding to produce two orbiting black holes. Another way is to detect the existence of black holes by monitoring the motion of bright companion stars and to measure the mass of black holes. In the past 50 years, about 20 black holes have been discovered using this method, both three to 20 times the mass of the sun.
It turns out that although the black holes do not glow, but the small partners around them are too high-profile, the surrounding accretion disk or companion stars are showing a different “gas field”: if the black hole and a normal star to form a near-two-star system, the black hole will reveal the teeth, with a strong “taste” The gas matter on the companion star is sucked in directly to form a suction disk that emits bright X-rays. These X-ray rays, like the “backlight” before these materials were swallowed by black holes, are the ones that have been a powerful clue to astronomers’ search for black holes over the years. To date, almost all star-level black holes in the Milky Way have been identified by X-rays from the gas of the black hole’s accretion companion star.
The theory suggests that there should be hundreds of millions of star-level black holes in the Milky Way, but in the black hole binary system, only a small fraction of the X-ray radiation can be emitted. When the black hole and its companion star are far away, our “big stomach king” also shows a calm and gentle side.
That being the case, how do you search for these flat static, i.e. black holes that do not accumulate star gas? Astronomers have given a whole new answer to the discovery of the largest star-level black hole.
The discovery of the star-level “King of Black Holes”, 15,000 light-years from Earth, is inextricably linked to a silent lying “great contributor” to LAMOST. “If you use an ordinary 4-meter telescope to find such a black hole, it will take 40 years at the same rate, which fully reflects the high observation already high efficiency of LAMOST. Liu Jifeng said.
As early as the 1960s and 1970s, he said, humans had mobilized a large number of observation resources to discover black holes, but because of the sensitivity of the equipment and the problems of massive data processing, the end result was little. Because of reality, scientists have come up with ways to use X-rays to identify black holes, but they have had trouble.
What to do? Finding new methods and finding a large number of black holes without X-ray radiation has become a hot and difficult topic in astronomy in recent years. At a critical moment, China’s independent development of the country’s major scientific and technological infrastructure Guo Shoujing telescope LAMOST came in handy.
We know that black holes are formed by gravitational collapses after the death of a large mass star. “When studying celestial bodies, scientists often have three observational dimensions: light and dark, color, and location. Bai Zhongrui, a senior engineer at the National Observatory of the Chinese Academy of Sciences, said the color is the basis for observations that scientists often use, and color is reflected in spectral characteristics. “In other words, the spectrum is like a ‘bar code’ for celestial bodies. Bai Zhongrui explained.
And collecting these huge amounts of “bar codes” is exactly what “king of the spectrum” – LAMOST is good at. LAMOST has 4,000 eyes (4,000 fibers) and can observe nearly 4,000 objects at a time, Bai said. In March 2019, LAMOST released 11.25 million spectra, which astronomers have hailed as the “king of the spectrum” with the highest spectral acquisition in the world.
“Work to do good things must first benefit.” It was LAMOST’s “astronomical weapon” that helped astronomers discover today’s protagonist, the “King of the Black Hole.”
In early 2016, researcher Zhang Wei, director of LAMOST’s Science Survey, and Han Zhanwen, director of the Yunnan Observatory, proposed using LAMOST to observe the binary spectrum, carry out a two-star system research program, and selected more than 3,000 stars in kepler’s solar region for two years of spectral monitoring. It was found that in an X-ray-radiation tranquil binary system (LB-1), a blue star with an eight-fold solar mass, which orbits an “invisible object” that also exhibits unusual spectral characteristics, is periodically moving around an “invisible object”.
There must be a story behind this B-star, and it’s moving around the invisible “who’s”? It’s really a black hole! Astronomers never let any of them down easily in their pursuit of the truth of the universe. After a brief excitable excitable interview, the researchers applied for observations from the Spanish 10.4-meter Canary Large Telescope and the U.S. 10-meter-caliber Keck telescope, further confirming the spectral nature of the B-type star.
Based on spectral information, the researchers calculated that the metal abundance of the B star was about 1.2 times that of the sun, about 8 times the mass of the sun, about 35 million years old, and 14,000 light-years away. Back with other evidence, the researchers calculated that there was an invisible object in the binary system that was about 70 times the mass of the sun, and that it could only be a black hole. Liu Jifeng said.
Subverting traditional perceptions
The story is not over yet.
According to current models of stellar evolution, black holes up to 25 times the mass of the sun are allowed to form at the sun’s metallic abundance, so the mass of the black hole in LB-1 has entered the “no-go zone” of existing stellar evolution theory. In other words, a single star black hole in the Milky Way should not be 20 times larger than the sun. LaMOST’s findings could mean that theories about the evolution of stars into black holes will be forced to rewrite, or that some mechanism of black hole formation has previously been ignored.
What is the truth? The answer is: continue to observe and verify. “Over the next two years of monitoring, LAMOST made 26 observations for the study, with a cumulative exposure time of about 40 hours. Liu Jifeng said.
Time is deep. The end result was a good result for LAMOST. To commemorate LAMOST’s contribution to the discovery of the giant star-level black hole, astronomers named the binary system, which contains the black hole, LB-1. Unlike other known star-level black holes, LB-1 has never been detected in any X-ray observations, and the black hole is 1.5 times the distance of its companion star. Using an observation of the source at the Chandra X-ray Observatory in the United States, the researchers found that the newly discovered black hole was a “champion” of a “calm and gentle” stellar black hole, which is very weak in acarcepic to its companion star.
What is the point of this discovery? LiGO, the U.S. Laser Interference Gravitational Wave Observatory, has discovered black holes dozens of times the mass of the sun by detecting gravitational waves since 2015, and in 2017, Rene Weiss, Kip Thorne and Barry Barish were awarded the Nobel Prize in Physics for their contributions to LIGO’s construction and gravitational wave detection.
‘THE LB-1 IS A BINARY SYSTEM OF X-RAY RADIATION, ‘ LIU SAID. ‘IT’S NOT FEASIBLE TO SEARCH FOR SUCH BLACK HOLES USING CONVENTIONAL X-RAY METHODS. Radial velocity monitoring has long been thought to have allowed the discovery of flat-static black hole binary, as confirmed by the discovery of the largest mass black hole to date. Using LAMOST’s large-scale sky-survey advantageand and speed monitoring method, it is believed that astronomers will discover a number of hidden flat-static black holes, thereby gradually uncovering the dark “family” and taking an iconic step towards studying the formation and evolution of black hole members and mass distribution.
“Next, using LAMOST’s extremely efficient observational efficiency, astronomers are expected to discover a large number of ‘hidden’ black holes, ushering in a new era of mass discovery of black holes. Liu Jifeng said. (Reporter Shen Hui)