When it comes to enjoying delicious food, black holes seem as messy as some toddlers.
That’s because a stunning new illustration shows when a star is swallowed by a cosmic giant, leaving a ring of dust that looks like crumbs on a plate.
This unfortunate stellar destruction produces what astronomers call a “tidal disturbance event”, which is accompanied by a burst of radiation that can exceed the combined glow of any star in the black hole’s host galaxy for months or even years.
This particular black hole, captured using X-rays emitted by a tidal disturbance event called J2150, is a type that has not been detected for a long time – a medium-mass black hole.
“The fact that we were able to capture this black hole as it engulfs a star provides an extraordinary opportunity to observe what would otherwise be invisible,” said Ann Zabludoff, co-author and professor at the University of Arizona.
“Not only that, but by analyzing flares, we can better understand this elusive category of black holes that may make up the majority of black holes at the center of galaxies.”
Devoured: This stunning new illustration shows when a star is eaten by a black hole, leaving a ring of dust that looks like crumbs on a plate
WHAT IS TIDE INTERFERENCE EVENT?
When a star gets too close to a black hole, the black hole’s strong gravity creates tidal forces that can tear the star apart.
In this event, known as a tidal disturbance, some of the stellar debris is flung out at high speed while the rest falls into the black hole.
This results in a distinct x-ray beam that can last for years.
After a star is destroyed by a tidal disturbance, the black hole’s strong gravitational force pulls away most of the stellar remnant.
The friction heats up this debris and creates large amounts of X-rays.
According to these X-rays, the amount of light decreases as stellar material falls above the black hole’s event horizon – the point at which no light or other information can escape.
Gas often falls into the black hole by spinning inward and forming a disk.
But the process that creates this disk structure known as the “accretion disk” remains a mystery.
Researchers have found that most X-rays are generated from material very close to the black hole.
In fact, the brightest matter can actually take as few stable orbits as possible.
By re-analyzing the X-ray data to observe the J2150 flare and comparing it with sophisticated theoretical models, the authors show that this flare actually resulted from an encounter between an unfortunate star and a medium-mass black hole.
The central black hole in question has a very low mass – for a black hole – weighing about 10,000 times the mass of the sun.
According to Sixiang Wen, a postdoctoral fellow at the University of Arizona’s Steward Observatory, the team was able to classify it as an intermediate black hole after measuring its mass and spin.
Dozens of tidal disturbance events have been observed in the centers of large galaxies that host supermassive black holes, and several have also been observed in the centers of small galaxies that may contain medium-sized black holes.
However, previous data have never been detailed enough to prove that a single tidal-breaking flare is powered by an intervening black hole.
“Thanks to modern astronomical observations, we know that the center of almost all galaxies similar to or larger than our own Milky Way galaxy has a central supermassive black hole,” said study co-author Nicholas Stone, senior lecturer at the Hebrew University in Jerusalem.
“These giants are 1 million to 10 billion times the mass of our sun, and they become a powerful source of electromagnetic radiation when too much interstellar gas falls near them.”
The mass of these black holes is closely related to the total mass of their parent galaxy, so the largest galaxies host the largest supermassive black holes.
“We still know very little about the existence of black holes at the center of galaxies smaller than the Milky Way,” said co-author Peter Jonker of Radboud University in the Netherlands.
“Due to observational limitations, it is difficult to find central black holes much smaller than 1 million solar masses.”
Although thought to be abundant, the origins of supermassive black holes are unknown.
One theory, however, is that medium-mass black holes could be the cores from which supermassive black holes grow.
Jonker added, “A better understanding of how many true black holes exist can help determine which theory of supermassive black hole formation is correct.”
When a star ventures too close to a black hole, the force of gravity creates strong tides that split the star into streams of gas (pictured), resulting in a catastrophic phenomenon known as tidal disturbance.
Measuring the spin of the J2150 is also important as it provides clues about how the black hole grows.
This one has a fast spin, but not the fastest, explains Zabludoff, which raises questions about how laps in this area come about.
“Perhaps a black hole formed this way and hasn’t changed much since then, or two medium-mass black holes have recently merged into this one,” he said.
“We know that the spins we’ve measured rule out scenarios where black holes grow over long periods of time by constantly eating gas or getting lots of quick gas snacks from random directions.”
In addition, the spin measurements allow astrophysicists to test hypotheses about the nature of dark matter, which is believed to make up most of the matter in the universe.
Dark matter may consist of unknown elementary particles that have never been seen in laboratory experiments. Candidates include a hypothetical particle known as an ultralight boson, Stone said.
“If these particles exist and have a mass within a certain range, they will prevent a medium-mass black hole from spinning rapidly,” he said.
“Still, the J2150 black hole is spinning fast. So our spin measurements exclude a broad class of theories about ultralight bosons and demonstrate the value of black holes as space laboratories for particle physics. ‘
In the future, new observations of tidal flares could allow astronomers to fill in gaps about the distribution of certain types of black holes.
New telescopes, both on Earth and in space, are expected to detect thousands of tidal disturbances every year.
“If most dwarf galaxies are found to contain medium-mass black holes, then they will dominate the speed of stellar tidal disturbance,” said Stone.
“By fitting the X-ray emission from this flare to a theoretical model, we can calculate the population of medium-mass black holes in the universe,” Wen added.
THE BLACK HOLE HAS A TRAIN, THE LIGHT CAN’T FORGET THIS POWERFUL
Black holes are so dense and attractive that no radiation can escape them – not even light.
They act as a powerful source of gravity sucking up dust and gases around them. Its strong pull is believed to be an orbiting star in the galaxy.
How they appeared is still poorly understood. Astronomers believe they could form when large gas clouds, up to 100,000 times larger than the sun, collapse into a black hole.
Many of these seed black holes then coalesce into much larger supermassive black holes that are at the center of every known massive galaxy.
Or, a supermassive black hole could originate from a giant star about 100 times the mass of the Sun, which eventually formed into a black hole after running out of fuel and collapsing.
When these giant stars die, they also become “supernovas,” giant explosions that throw matter from the star’s outer layers into space.