Astronomers have reviewed the first black hole with a stellar mass ever identified and found that it is at least 50% more massive than we thought.
The black hole in the Cygnus X-1 X-ray binary system has been recalculated to fit 21 times the mass of the Sun. This makes it the most massive black hole with a stellar mass ever detected without the use of gravitational waves and forces astronomers to rethink how black holes form.
Cygnus X-1 was first discovered as an X-ray source in 1964, and its black hole status has become the subject of a bet between astrophysicists Stephen Hawking and Kip Thorne.
The scientists later validated the interpretation of the black hole of the object’s nature, concluding that the X-ray emission was produced by the black hole that tasted a binary companion.
It became one of the most studied black holes in the sky, and astronomers thought it was quite well understood: an object about 6,070 light-years away, with a mass of 14.8 solar masses and a supergiant blue binary companion. called HDE 226868 around 24 solar masses.
According to the new observations, I was wrong.
Astronomers have made new parallax observations of the system, watching how it appears to “sway” in the sky as the Earth orbits the Sun, using a very long line matrix, a collection of radio telescopes that act together as a collection vessel of size. continental.
Finally, their observations showed that Cygnus X-1 is a fairly significant distance further than I thought. Which means that the objects themselves are significantly larger.
“We used radio telescopes to make high-precision measurements of the Cygnus X-1 – the first black hole ever discovered,” said astronomer James Miller Jones of the International Center for Radio Astronomical Research (ICRAR) in Australia.
“The black hole has been in orbit for several days with a massive accompanying star. Following the orbit of the black hole for the first time in the sky, we refined the distance to the system, placing it over 7,000 light-years from Earth.
“This meant that the black hole was more than 20 times larger than the mass of our Sun, making it the most massive black hole with a stellar mass ever discovered without the use of gravitational waves. This challenges us to ideas about how massive stars evolve to form black holes. “
Previously, the most massive black hole with an electromagnetically detected stellar mass was the M33 X-7, with a speed 15.65 times faster than the mass of the Sun. At the time of its discovery, even the M33 X-7 caused our black hole formation patterns.
The scientists concluded that as the massive star that collapsed to form the black hole reached the end of its life, it lost mass more slowly than the models suggested. They think something similar for Cygnus X-1.
“Stars lose mass in the environment through stellar winds that move away from their surface. But to make such a heavy black hole, we need to reduce the amount of mass that bright stars lose during life,” said theoretical astrophysicist Ilya Mandel from the ARC Center of Excellence in Gravitational Wave Discovery (OzGrav) in Australia.
The precursor star of the black hole Cygnus X-1 would have started at about 60 solar masses, throwing its outer material before the core collapsed directly into the dense object it is today, bypassing a supernova explosion.
Now, he is locked in an incredibly close orbital dance, 5.6 days, with his supergiant blue companion, who now also has a revised table, bringing him up to 40 solar masses.
This is massive enough that it should also one day end up as a black hole, forming a black binary hole similar to those seen in fusions that generate gravitational waves.
However, the good is unlikely to merge soon. Refined measurement of distance will also allow astronomers to recalculate other features of the Cygnus X-1. In a separate paper, astronomers found that it spins almost as fast as the speed of light. It’s faster than any other black hole ever measured.
This is in direct contrast to gravitational wave tracks, which have very slow or misaligned rotations. This suggests that Cygnus X-1 followed a different evolutionary path from the black hole tracks we saw merging.
Given the distance between Cygnus X-1 and HDE 226868, the researchers calculated that the pair is unlikely to merge in a time frame equal to the age of the Universe – 13.8 billion years.
Studying the system now, before the second collapse of the black hole, presents a rare opportunity to understand the binary of black holes.
“Observations like these tell us directly a lot about the evolutionary paths that are possible in making double black holes, some of which have regularly found gravitational wave detectors on the ground, such as LIGO and Virgo,” said physicist Ashley Ruiter of at the University of New South Wales Canberra in Australia, who was not involved in the research.
“It’s great that we can still catch binary with electromagnetic light ‘in action’ before it forms a double black hole – it helps us refine our theories about the evolution of nearby binary stars.”
The team ‘s research was published in Science.