The Atlas Atlas twin telescopes in Hawaii detected on June 16 "a spectacularly bright anomaly" in the constellation Hercules, about 200 million light-years away.
Called AT2018cow or simply "the cow", this object quickly exploded and disappeared quickly.
At first, experts considered it could be a supernova, but "what we observed challenged our current knowledge of star death," said lead author Raffaella Margutti in a statement from the American University of Northwestern.
An international team analyzed the event, combining images from various sources, including hard X-rays (high energy and lower wavelengths) and radio waves.
After the analysis, experts believe that the telescopes could capture "the exact moment" in which a star collapsed to form a compact object, such as a black hole or a neutron star with a powerful magnetic field that absorbs all surrounding material.
The stellar residues, approaching and rotating around the so-called "event horizons" of the object, were the cause of extremely bright brightness.
Several telescopes participated in the follow-up of the event, among them SOAR in Chile, where the observer, Régis Cartier, assured that "almost from the beginning" knew that this explosion was "special."
"It was fast, blue and bright, unlike other supernovae seen before, I left everything I was working on to focus on understanding this event," he said.
Detecting this rare event will help astronomers better understand the physics that works the first moment of creating a black hole or a neutron star.
"By theory, we know that when a star dies, a black hole or a neutron star forms, but we never saw them soon after they were born." Never, "said Margutti.
The results of the study were presented today at the annual meeting of the American Astronomical Society and will be published in the Astrophysical Journal.
Margutti recalled that the observed event was "abnormally bright" – ten to a hundred times more than a typical supernova – and also exploded and disappeared much more rapidly than other known star explosions.
The data indicate that in just 16 days the object had already emitted most of its energy, a lapse that can be described as a blink of an eye if we take into account that in the Universe some phenomena last for millions or billions of years. years
The team used several telescopes to look more closely at the composition of the object and found "clear evidence" of the presence of hydrogen and helium, which excluded that the blast was the result of two objects merging, such as those producing gravitational waves.
In addition, astronomers were able to identify typical patterns of object-attracting objects in their environment, whether it's a black hole or a neutron star, according to a statement from the European Space Agency (ESA), which used its space-ray observatory . X XMM-Newton to study the event.
Experts will continue to analyze data from XMM-Newton to try to understand the nature of what happened, said study co-author Giulia Migliori of the Italian University of Bologna.
The black holes "leave characteristic X-ray traits that we could detect in our data," said Migliori, quoted by ESA.