An international team of astrophysicists may have found a new way to destroy a star while searching for sources of powerful gamma-ray bursts (GRBs). While most gamma-ray bursts come from explosions of massive stars or mergers of neutron stars, the researchers concluded that GRB 191019A instead came from colliding stars or stellar remnants in the thick medium surrounding a supermassive black hole in the core of an ancient galaxy. The demolition derby-like setting marks a long assumed but never-before-seen way to destroy a star and create a GRB.

The research was published in the journal Nature Astronomy. The research team, led by Radboud University in the Netherlands, included astronomers from Northwestern University.

“For every hundred events that fit the traditional gamma-ray burst classification scheme, there is at least one outlier that puts us in a loop,” said Wen-Fai Fong, a Northwestern University astrophysicist and co-author of the study. about the astonishing variety of explosions the universe can make.

“Discovering these extraordinary events surrounding supermassive black holes in dense star systems, particularly in the cores of galaxies, is undeniably exciting,” said Giacomo Fragione, a Northwestern University astrophysicist and co-author of the study. “This astonishing discovery gives us an exciting look at the complex dynamics at work in these cosmic environments, turning the complex dynamics at work into factories for events that were otherwise thought impossible.”

Fong is an associate professor of physics and astronomy at the Weinberg College of Arts and Sciences at Northwestern and a member of the Center for Interdisciplinary Research and Research in Astrophysics (CIERA). Fragione is Associate Professor at CIERA. Other Northwestern co-authors include both Ph.D. Anya Nugent and Gillian Rastinejad. astronomy students and members of Fong’s research group.

Most stars die in one of three predictable ways, depending on their mass. When relatively low-mass stars like our Sun age, they shed their outer layers and eventually disappear to form white dwarf stars. More massive stars, on the other hand, burn brighter and explode faster in devastating supernova explosions, creating super-dense objects such as neutron stars and black holes. A third scenario occurs when two such stellar remnants form a binary system and eventually collide.

But new research suggests there may be a fourth option.

“Our results show that stars can die where they can collide in the densest regions of the universe,” said astronomer Andrew Levan of Radboud University. “This is interesting for understanding how stars die, and for answering other questions like what unexpected sources we can detect on Earth might create gravitational waves.”

Ancient galaxies have long passed their star-forming era, but few massive stars remain. However, their cores are filled with stars and super-dense stellar remnants such as white dwarfs, neutron stars, and black holes. Astronomers have long suspected that in a hive of frenetic activity surrounding a supermassive black hole, it’s only a matter of time before two stellar objects collide to create a gamma-ray burst. But the evidence for this type of fusion remains unclear. Source