the sciences. – Intermediate mass black holes eat stars with stingers – Publimetro México

Madrid, 25 years old (Europe Press)

Northwestern University astrophysicists modeled black holes of different masses and threw stars (the size of our Sun) in front of them to see what would happen. They publish the results in The Astrophysical Journal.

They found that when a star approaches an intermediate-mass black hole, it becomes trapped in its orbit. Then, the black hole begins its long and violent meal. Every time the star spins, the black hole takes a piece of it, pulling the star apart with each pass.

In the end, only the distorted and incredibly dense core of the star remains. At that moment, the black hole ejects debris. The remains of the star fly to safety across the galaxy.

Not only do these new simulations point to the unknown behaviors of intermediate-mass black holes, but they also provide astronomers with new clues to help finally locate these hidden giants in the night sky.

“Obviously, we can’t directly observe black holes because they don’t emit light, so instead we have to look at the interactions between black holes and their surroundings,” said Fulya Kyroglu of Northwestern University, who led the study.

“We’ve found that stars go through multiple clips before they’re cast,” he continues. “After each pass, it loses more mass, causing the light to glow as it ruptures. Each glow is brighter than the last, creating a signature that can help astronomers find them.”

Kiroglu, a graduate student in astrophysics at Northwestern University’s Weinberg College of Arts and Sciences and a member of the Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA), presented the study at the American Physical Society (APS) meeting.

Although astrophysicists have shown the existence of both lower-mass and higher-mass black holes, intermediate-mass black holes have remained elusive. The remaining black holes are formed from stars when supernovae collapse, and have between 3 and 10 times the mass of our sun.

At the other end of the spectrum are supermassive black holes, which lie at the center of galaxies, millions to billions of times the mass of our sun.

If they exist, intermediate-mass black holes would lie somewhere between: 10 to 10,000 times more massive than the remaining stellar black holes, but nowhere near as massive as supermassive black holes. Although these intermediate-mass black holes should theoretically exist, astrophysicists have yet to find definitive observational evidence.

Their existence is still being debated, Kiroglu said. Astrophysicists have discovered evidence of their existence, but this evidence can often be explained by other mechanisms. For example, what appears to be an intermediate-mass black hole could actually be an accumulation of black holes. stellar mass black.

To explore the behavior of these elusive objects, Kiroglu, Frederic Rasio, Joseph Cummings Professor of Physics and Astronomy at Weinberg and CIERA member and co-author of the paper, and their team developed new hydrodynamic simulations.

First, they created a model of a star made up of many particles. Then they sent the star toward the black hole and calculated the gravitational force acting on the particles as they approached the star.

“We can identify which particle is associated with the star and which particle is perturbed (or no longer associated with the star),” says Kiroglu.

Using these simulations, Kiroglu and his team found that stars can orbit an intermediate-mass black hole up to five times before they are finally ejected. With each revolution around the black hole, the star loses more and more of its mass as it is torn apart.

The black hole then ejects the debris, moving at breakneck speed, into the galaxy. This repeating pattern will create an impressive light show that will help astronomers identify — and prove — the existence of intermediate-mass black holes.

“It’s surprising that the star doesn’t completely tear itself apart,” Kiroglu admits. “Some stars may get lucky and survive the event. The velocity of ejection is so high that these stars can be identified as hypervelocity stars, which are observed in the centers of galaxies.

Next, Kiroglu plans to simulate different types of stars, including giant stars and binary stars, to explore their interactions with black holes.