This stellar slaughter was spotted by scientists who study the X-rays bouncing around the swirling disk of matter surrounding the giant black hole.
The method used to analyze this event - named Swift J1644+57 - could help solve the mystery of how the largest black holes in the universe grew to such enormous sizes, the authors of the new research said.
At the core of almost every galaxy lies a monster black hole - in some cases, the largest black holes in the universe, millions to billions of times the mass of the sun.
Astronomers think vast amounts of energy from these supermassive black holes can influence the evolution of the galaxies in which they live.
Although nothing can escape a black hole after falling inside, not even light, it's possible for material around a black hole to radiate light that astronomers can see.
Violent motion within the so-called accretion disks, the expanses of gas and dust swirling around black holes, can generate bright flares of light, as well as jets of material that shoot away from the black hole at nearly the speed of light.
Most of what astronomers know about supermassive black holes comes from studying black holes that are actively devouring or accreting matter. However, these active giants make up only about 10 percent or less of supermassive black holes, the authors of the new paper (Relativistic Reverberation in the Accretion Flow of a Tidal Disruption Event) told Space.com.
In contrast, about 90 percent of known supermassive black holes are dormant, meaning that they are not actively consuming matter and, consequently, do not give off any detectable radiation.
However, sometimes a star drifts too close to a dormant black hole, and the star's ensuing destruction, known as a tidal disruption event, triggers spectacular fireworks.
These cataclysms can provide astronomers with information about this vast population of mysterious supermassive black holes.
Any details from dormant black holes are potentially valuable to astronomers in their efforts to understand all types of black hole activity. Scientists would especially like to understand the rates of spin for both active and dormant supermassive black holes.
This is because scientists have different theories about how black holes grow in size, and these different ideas predict different spins for the black holes, study lead author Erin Kara, an astrophysicist at the University of Maryland, said.
Previous research into the light from active black holes revealed that many of the objects are spinning rapidly.
Astronomers now want to measure the rate at which normally dormant black holes whirl; this will help researchers get a more complete picture of black hole spin, Kara said.
For the new research, Kara and her colleagues examined a black hole that was caught in the act of swallowing a star that got too close (the first such discovery), using old high-energy X-ray data from NASA's public archives.
Swift J1644+57, first detected in 2011, happened about 3.9 billion light-years from Earth in the direction of the constellation Draco.
The researchers used a new technique called X-ray reverberation mapping to chart the inside of the black hole's accretion disk.
This method resembles how dolphins and bats map their surroundings by emitting ultrasonic waves and measuring the amount of time it takes for the echoes to return.
In X-ray reverberation, the astronomers investigated small delays in the arrival time of X-rays emitted within the disk that reflected off iron atoms in the disk.
This new kind of analysis suggested the black hole is a few million times the mass of the sun.
In addition, the scientists unexpectedly discovered that the X-rays appear to come from deep within the accretion disk, very near the black hole, Kara said.
Conventional wisdom among astronomers has long held that, during a tidal-disruption event, high-energy X-rays are created further away from the black hole in the relativistic jets - powerful bursts of particles ejected from the black hole at nearly the speed of light.
Furthermore, the researchers found the black hole was gorging on the star at a rate 100 times greater than a theoretical maximum known as the Eddington limit.
This is the point at which the energy given off by matter rushing toward a black hole should curb the amount of matter feeding that black hole.
Increasingly, research suggests black holes can overcome the Eddington limit for so-called super-Eddington growth rates.
So far, Kara and her colleagues have not actually been able to use X-ray reverberation mapping on a tidal-disruption event to measure dormant black-hole spin.
Still, they say the method could directly measure the speed and direction of dormant black-hole spin in the near future.
In the future, the researchers want to attempt X-ray reverberation mapping on additional tidal-disruption events.
The scientists detailed their findings (Relativistic Reverberation in the Accretion Flow of a Tidal Disruption Event) online June 22 in the journal Nature.