Let Hawking bet what kind of precise measurement results came about the black hole that lost

The latest accurate measurement results of Cygnus X1 are here

What was the black hole that made Hawking lose

　　Author: reporter Qi Fang

【Technological frontier】　

Our newspaper, Beijing, February 19 (Reporter Qi Fang)

Cygnus X1 (Cygnus X-1) is the first black hole with a

star discovered by humans.

Scientists have been conducting continuous research on it for decades.

In the early morning of February 19th, Beijing time, three articles in the international scientific journals "Science" and "Astrophysical Journal" jointly released the latest accurate measurement results of it-from Australia, the United States and China The three teams independently made the most accurate measurements and restrictions on the distance, mass, spin and evolution of the black hole, and found that this system contains a black hole 21 times the mass of the sun, and its rotation speed is extremely close to the speed of light.

This is the only X-ray binary star system with a black hole that has a mass of more than 20 times the mass of the sun and rotates so fast that humans have discovered and confirmed.

　　Zhao Xueshan and Zheng Xueying, researchers and students of Gou Lijun, National Astronomical Observatory of the Chinese Academy of Sciences, are the main contributors of this research.

According to Gou Lijun, Cygnus X1 was discovered in 1964 as an X-ray binary star system-including a compact celestial body capable of generating X-ray sources and a blue giant star.

The famous physicists Thorne and Hawking once made a bet on whether this dense celestial body was a black hole or a neutron star. Hawking firmly believed that it was a neutron star.

In the 1990s, more and more observational evidence showed that this dense object was a black hole, and Hawking signed to admit defeat.

　　For decades, scientists have been hoping to accurately "draw" the nature of this black hole.

In 2011, Gou Lijun and his collaborators attempted to accurately measure the nature of this black hole for the first time. Gou Lijun said: "The result we got at that time was that the distance between this black hole system and the earth was 6067 light-years and the mass was 14.8 times the mass of the sun , And found that the black hole’s horizon is rotating at 72% of the speed of light.” In 2013, the European Aviation Agency’s Gaia (GAIA) satellite was launched into space, planning to accurately measure the distance of 1 billion stars in the Milky Way.

Its measurements of Cygnus X1 show that it is about 7,100 light years away from the earth.

　　This time, the team led by Professor Miller Jones of Curtin University in Australia mainly completed the measurement of the distance of the X1 Cygnus black hole.

The team used the U.S. Very Long Baseline Interferometric Array (VLBA) to make observations. After a series of complex scientific calculations, the team finally obtained the latest distance of the Cygnus X1 black hole at 7,240 light-years, with an accuracy of 8%.

On this basis, the cooperative team reanalyzed the optical data and found that the mass of the black hole has increased by nearly 50%, 21 times the mass of the sun, with an accuracy of 10%.

This is the only black hole X-ray binary system with a black hole mass over 20 times the mass of the sun discovered by humans.

　　The research team led by Gou Lijun mainly studied the rotation speed of this black hole, and the research results were published in Science and Astrophysical Journal at the same time.

He said: "The rotation of a black hole only affects a range of about a few hundred kilometers close to the black hole's visual interface. Therefore, it is necessary to use the X-ray band data with higher photon energy generated by the accretion disk in this area to infer." The research team found that and Compared with previous research results, the black hole's self-transition is faster-the black hole's visual interface is spinning at least 95% of the speed of light. This is the only known black hole system that rotates at such a high speed.

In another article, scientists speculated that in order to form a black hole with such a weight and rotating extremely fast, the stellar wind loss should be several times smaller than previously estimated, and the mass of the precursor star of this black hole may be 60 of the mass of the sun. Times.

　　Gou Lijun believes that accurate measurement of system parameters provides humans with an opportunity to compare with black holes detected by gravitational waves.

"The rotation of Cygnus X1 is extremely fast. This is completely different from the black hole system discovered by gravitational waves. This also means that this system is likely to have a completely different formation mechanism from the gravitational wave system."