‘Spaghettified’ star wrapped around a black hole spotted for the first time
A black hole tears down a star, leaving a long string of star material, which then wraps itself around the black hole. (Credit: NASA/CXC/M. Weiss (Image credit: NASA / CXC / M. Weiss)
For the first time, filaments of material wrapped around a supermassive black hole have been found, implying that a star bound by the black hole’s gravity has recently been destroyed via “spaghettification.”
Astronomers believe that the tidal disruption effect occurs because the black hole’s gravity pulls more strongly on the side of the star closest to the black hole. The black hole rips the star apart before swallowing in its mass, turning it into a long filament in the process.
Previously, the only evidence of such a situation, in which a star met a violent demise by traveling too close to the center of a galaxy, came in the form of short bursts of electromagnetic radiation emitted by supermassive black holes.
However, scientists have just recently discovered evidence of a physical filament from a star in the black hole’s vicinity. A team of astronomers from the Netherlands Institute for Space Research (SRON) and Radboud University in the Netherlands successfully detected such a spaghettified star in spectral absorption lines around the poles of a distant black hole in this study, published on March 24 in the journal Monthly Notices of the Royal Astronomical Society.
Absorption lines are unusually dark lines found in a continuous spectrum of electromagnetic radiation emitted by a source, in this case a black hole. These lines emerge when a material absorbs a part of the electromagnetic radiation (in this case, the spaghettified star) obscures the source.
When looking at the black hole’s rotational pole, the scientists noticed the spectral absorption lines. The observation suggested that a strand of material was wrapped around the black hole numerous times, like a yarn ball, the scientists said in a statement. The team believes that this debris represents the torn star, which is orbiting the black hole before disappearing inside it.
Disks of accreted matter are known to exist around the equators of black holes. The disk, made of material drawn to but not yet swallowed by the black hole, orbits the equator at high speeds, emitting heat, X-rays, and gamma-rays in the process.
The latest study’s authors, on the other hand, claim that the material they were looking at was not part of the accretion disk.
“The absorption lines are narrow,” said Giacomo Cannizzaro, the paper’s primary author. “They are not broadened by the Doppler effect, like you’d expect when you would be looking at a rotating disk.”
Because of the fast motion of the material in the accretion disk, the Doppler effect stretches or shrinks the electromagnetic waves depending on whether the source is moving towards or away from the observer. As a result, the light generated by the moving portion of the accretion disk would be brighter. However, the scientists found no evidence of this.
According to the researchers, they knew they were facing the black hole’s pole because they could detect X-rays. “The accretion disk is the only part of a black hole system that emits this type of radiation,” the statement said. “If we were looking edge-on, we wouldn’t see the accretion disk’s X-rays.”
Supermassive black holes, which are millions or billions of times heavier than the sun, are thought to lurk in the center of most galaxies. They expand over billions of years, consuming everything that falls into their gravitational embrace. Astronomers can detect black holes by the brilliant X-rays they emit as they devour gas and stuff in their surroundings.
Stars that orbit in the center of galaxies may occasionally get too close to black holes and become trapped by their gravity. They are pulled closer and closer to the black hole, eventual death from spaghettification.