This artist's impression shows a binary system containing a stellar-mass black hole called IGR J17091-3624. The strong gravity of the black hole, on the left, is pulling gas away from a companion star on the right. This gas forms a disk of hot gas around the black hole, and the wind is driven off this disk at 20 million mph. CREDIT: NASA/CXC/M.Weiss
Scientists claim to have successfully measured the fastest wind discovered so far, which blows off around a stellar-mass black hole.
The discovery is expected to shed more light on understanding the behavior of this type of black holes.
The wind, which the astronomers clocked using NASA's Chandra X-ray Observatory, is moving at a record-breaking speed of about 20 million mph (32 million kph) or about 3 percent of the speed of light. That's almost 10 times faster than what had ever been seen from a stellar-mass black hole, scientists said.
The fast-moving wind surprised the scientists as they themselves were not expecting to see such powerful winds from a small black hole like the one in question.
It's a surprise this small black hole is able to muster the wind speeds we typically only see in the giant black holes, said co-author Jon M. Miller, also from the University of Michigan. In other words, this black hole is performing well above its weight class.
According to NASA, the wind speed in IGR J17091 equals some of the fastest winds, generated by supermassive black holes.
This is like the cosmic equivalent of winds from a category five hurricane, said Ashley King from the University of Michigan, lead author of the study published in the Feb. 20 issue of The Astrophysical Journal Letters.
Steller-mass black holes, born as a result of massive star collapses, usually weigh between five and 10 times the mass of the sun. The steller-mass black hole that powers this superfast wind is named as IGR J17091-3624 or IGR J17091 in short. It's a binary system in which a sun-like star orbits the black hole. It is found in the hump of the Milky Way galaxy, about 28,000 light years away from the Earth.
Scientists have found out yet another surprising fact, which, according to them, is quite unanticipated.
The wind, which comes from a disk of gas surrounding the black hole, may be carrying away more material than the black hole is capturing.
Contrary to the popular perception of black holes pulling in all of the material that gets close, we estimate up to 95 percent of the matter in the disk around IGR J17091 is expelled by the wind, King said.
What makes the wind from IGR J17091 different from the hurricanes on the Earth is the various directions it's blowing in. Because of the same reason, it's also different from a radio jet, where material flows in highly focused beams perpendicular to the disk, often at nearly the speed of light.
Although a radio jet was seen coming from IGR J17091 at other times, observations made with the National Radio Astronomy Observatory's Expanded Very Large Array showed that the radio jet from the black hole was not present when the ultra-fast wind was blowing.
This revelation corresponds with observations of other stellar-mass black holes, confirming that the production of winds can stifle jets, according to scientists.
The high speed for IGR J17091's wind was estimated using a spectrum made by Chandra in 2011. A Chandra spectrum of iron ions made two months earlier didn't show any evidence of the high-speed wind, which suggests that the wind probably turns on and off over time.
The Chandra X-ray Observatory, managed by NASA's Marshall Center for the Science Mission Directorate, is part of NASA's fleet of Great Observatories along with the Hubble Space Telescope, the Spitizer Space Telescope and the now deorbited Compton Gamma Ray Observatory.
Chandra allows scientists from around the world to obtain X-ray images of exotic environments to help understand the structure and evolution of the universe.