The record mass of the Cygnus X-1 black hole surprised astronomers

Cygnus X-1 It is one of the most famous black holes, but it does not stop providing surprises. It was first discovered, especially from the X-ray detector on a suborbital rocket in 1964. It is the closest planet in our own galaxy (it is thought to be about 6000 light-years).

He also starred Famous bet (Subscribe to Magazine Penthouse) Among physicists Kip Thorne with Stephen HawkingIn 1974, he thought it was not a black hole, but in 1990, decades later, he had to admit his mistake.

it is Black hole Form a binary star system with a companion star Blue giant Both revolve in very close orbits, equivalent to 1/5 of the distance from the earth to the sun (completed every 5.6 days). It is one of the most powerful X-ray emission sources in the sky.

So far, it has been thought that the mass of Cygnus X-1 is about 14.8 times that of the sun, but an international team of astronomers found that its mass is much higher: it has several 21 solar mass, Which poses a challenge to the current stellar evolution model.Details will be published in the magazine this week science with Astrophysical Journal.

“Our research provides a new method for measuring the so-called triangular parallax, placing Cygnus X-1 at a distance of 20% from the earth (7,200 light years), therefore, this black hole is much larger than previously thought: its correction value is 21 +/- 2 solar masses,” an author explained to SINC, Maria Rioja, National Astronomical Observatory (OAN) Now at the International Radio Astronomy Research Center (ICRAR), from the University of Western Australia.

“He added that it is already the highest-mass stellar black hole known in the Milky Way, but through this work, it has become the largest mass electromagnetically detected inside and outside the Milky Way (rather than through gravitational waves), breaking a new record.”In other words, it is The most massive stellar black hole detected without gravitational waves.

Ten antennas of VLBA in the United States

In order to measure distances and conduct research, the author used observational data obtained through observations in 2016. Very Long Baseline Array (VLBA), Is a radio interferometer composed of 10 parabolic antennas distributed throughout the United States. They can work together like an instrument.

” Very Long Basis Interferometry (VLBI) Using this instrument can provide the highest resolution images and the most accurate position measurement in astronomy,” Rioja emphasized.”Equivalent to being able to distinguish the figure of a person on the moon I took a picture from the earth and wanted to know if it was waving and watching the change of arm position.”

With the help of Triangular Parallax, This is a reference method that can accurately measure the astronomical distance through the obvious changes in the position of objects in the sky seen from the earth during the year, taking into account the orbit of our planet orbiting the sun.

The lead researcher said: “If we see the same object from different locations, we can calculate the distance between it and us by measuring how far the object moves relative to the background.” James Miller Jones An example from Curtin University in Australia and ICRAR: “If you point your finger at something and see it with only one eye at a time, you will find that it seems to jump from one place to another. This is indeed the same the rules.”

Miller-Jones said: “(In 2016, we observed the full orbit of the black hole and used other orbits obtained from the same system in 2011), therefore, we found that it is farther away than previously thought. Significantly bigger.”

Therefore, it has been proved that Cygnus X-1 is the most massive stellar black hole known using electromagnetic technology, and its rotation speed is very fast, very close to the speed of light. Faster than other black holes Found so far.

Review model

The problem is that its 21 solar masses do not match what people think. Stellar evolution. The authors say that for the existence of such a huge black hole in the Milky Way, the mass is lost through the Milky Way. Stellar wind and explosion During the evolution of its parent star (it should have collapsed thousands of years ago, and the remaining remains were replaced by Cygnus X-1), its volume must be smaller than the value predicted by the current model.

Rioja said: “Our observations assume that the estimated mass of the black hole has increased by about 40%, which is difficult to match with our current understanding of stellar evolution.” The mass loss rate of black hole progenitors should be greatly reduced (Between 30% and 70%); therefore, it is necessary to review the proposed evolution model of massive stars”.

The astronomer recalled that theory and observation are complementary to each other and promote scientific progress. She believes that new data will put aside the new generation of instruments already in use, such as Square kilometer array (Ska, It will begin construction in Australia and South Africa next year), and the next-generation VLA observatory with more antennas (ngVLA).