Nearby black holes and their stellar companions form a gallery of astrophysical thieves in this new visualization from NASA.
Stars born with more than 20 times the mass of the sun end their lives as black holes. As their name suggests, black holes don’t shine on their own because nothing can escape them, not even light. Until 2015, when astronomers first detected merging black holes through space-time ripples called gravitational waves, the primary way to find these ebony puzzles was to search for them in binary systems where they interacted with companion stars. And the best way to do that was to look in x-rays.
This visualization shows 22 X-ray binaries in our Milky Way galaxy and its closest neighbor, the Large Magellanic Cloud, which host confirmed stellar-mass black holes. The systems appear on the same physical scale, demonstrating their diversity. Their orbital motion is accelerated nearly 22,000 times, and viewing angles replicate the way we see them from Earth.
When associated with a star, a black hole can collect matter in two ways. In many cases, a stream of gas can flow directly from the star to the black hole. In others, like the first confirmed black hole system, Cygnus X-1, the star produces a dense outflow called the stellar wind, from which some of the black hole’s intense gravity gathers. So far, there is no clear consensus on the mode used by GRS 1915, the big system at the center of the visualization.
Upon arriving at the black hole, the gas orbits and forms a large flattened structure called an accretion disk. The GRS 1915 accretion disk may extend over 50 million miles (80 million kilometers), more than the distance from Mercury to the sun. The gas in the disk heats up as it slowly spins inward, shining in visible, ultraviolet, and finally X-ray light.
The colors of the stars range from blue-white to reddish, representing temperatures five times hotter to 45% cooler than our sun. Because accretion disks reach even higher temperatures, they use a different color scheme.
While the black holes are shown on a scale reflecting their masses, all are shown much larger than they actually are. The Cygnus X-1 black hole weighs about 21 times as much as the sun, but its surface, called the event horizon, only extends about 124 kilometers. The oversized spheres also mask visible distortions that would be produced by the gravitational effects of black holes.
Image: The black hole bounty captured in the center of the Milky Way
Provided by NASA’s Goddard Space Flight Center
Quote: NASA Visualization Rounds Up Best Known Black Hole Systems (2022, May 3) Retrieved May 3, 2022 from https://phys.org/news/2022-05-nasa-visualization-rounds-best-known -black.html
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