black hole 224 88.
(photo credit: Courtesy)
Astrophysicists from Tel Aviv University have joined colleagues in the US and Germany to discover the heaviest stellar black hole to orbit with a companion star, possessing a mass 16 times that of our sun. The find is all the more remarkable because models to explain such black holes' formation from massive stars have difficulty producing anything greater than 10 solar masses.
A black hole is a region of space in which the gravitational field is so powerful that nothing can escape. The name is derived from the fact that even electromagnetic radiation such as light is unable to escape, rendering the inside of it invisible.
The discovery was published Wednesday evening in the prestigious journal Nature. Prof. Jerome A. Orosz of San Diego State University, Avi Shporer and Prof. Tsevi Mazeh of TAU, along with others from Harvard, Yale, the US National Optical Astronomy Observatory and the Max Planck Institute in Germany found the black hole and its companion in the spiral galaxy Messier 33.
"I am excited by the fact that we are able to study black holes whose existence we were able to imagine only thanks to Einstein's General Theory of Relativity," said Mazeh. "New space vehicles and giant telescopes make it possible for us to research space systems that seem to have come from a science fiction film. Reality surpasses the human imagination... Astronomical measurements allow us to take a peek into the expanse of space and discover powerful events much greater than those occurring on Earth. I hope these discoveries will lead scientists and even all of human society to a degree of modesty and wonder when we stand opposite the wonders of the universe."
The companion star passes directly in front of the black hole on its orbit, eclipsing the black hole's X-ray emission. This allowed the team to calculate the pair's masses more accurately than usual. The companion star is also the most massive known, weighing in at 70 solar masses. This distant binary represents an important system in the study of high-mass stellar black holes and X-ray binaries.
Black holes can be detected if they interact with matter outside, for example by drawing in gas from an orbiting star. The gas spirals inward, heating up to very high temperatures and emitting large amounts of radiation in the process.
Messier 33 is three million light years from Earth. The black hole and its companion tumble over each other once every three and a half days.
The scientists observed the phenomenon with the Chandra space telescope, which belongs to the US National Aeronautical and Space Administration, and the giant Gemini telescope located on a mountain in Hawaii. Mazeh, director of the Sackler Institute for Astronomy, and his research student Shporer participated.
Black holes that move together with companions have been known for 40 years. According to astrophysical theory, such a relationship is launched when two stars revolve around each other.
The heavier one ends its life by becoming a supernova, created by the implosion of the star that creates strong light that is billions of times more powerful than that of our sun's. At the end of the supernova's life, the heart of the star becomes a black hole that continues to revolve around its companion. Material passes from the companion to the black hole and falls at incredible speeds inside it. The material reaches a temperature of millions of degrees and releases X-rays before it enters the orifice. These rays were picked up by the Chandra.