Today, Monday, the scientific journal “Nature” published the results of a study in which scientists identified a new method for the death of stars, which is embodied in what looks like a real collision in the heart of the galaxy.
“Instead of a natural end, stars can die in a collision,” Professor Andrew Levan of the Netherlands’ Radboud University, who is the lead author of this recently published study, told AFP.
Normally, the fate of a star depends on its mass. And the astrophysicist explains, “The matter ends with large stars in a supernova (massive explosion), while stars with low mass, such as the sun, are extinguished in the form of a white dwarf.”
These stars can also, in more rare stations and in the case of neutron stars, merge with each other when in a binary system, as a pair of objects born very close together.
But the matter is different here, with the observation in October 2019 of a gamma-ray burst, in a stream of rays of enormous energy originating from a distant galaxy located in the direction of the constellation Aquarius.
Depending on its duration, which ranges from less than two seconds to several minutes, such an event would signify, respectively, the merger of two neutron stars or the explosion of a large supernova. This phenomenon, named GRB191019 and lasting more than 1 minute, is assumed to belong to the second category.
But astronomers did not notice any signs of a supernova in the galaxy from which the burst of energy was launched and located about 2 billion light-years from Earth. However, nothing surprising, because this galaxy, so old, forms almost no stars anymore, and thus no longer produces massive stars that would likely end up in a supernova.
The long observation of this event gave the key to solving the mystery. The phenomenon occurred very close to the galactic core, less than 100 light-years away. For comparison, our solar system is about 27,000 light-years from the center of the galaxy.
Andrew Levan explains that this galaxy’s nucleus is “a very dense region, which can contain tens of millions of stars, which can collide or scatter,” especially since the “compact objects” that inhabit it, white dwarfs, neutron stars and small black holes, are subject to the gravitational force of the hole. The super black, lurking in the center of the galaxy.
This led the international team of researchers to conclude that the two celestial bodies whose collision caused the gamma-ray burst “formed in different places from each other and met” in the heart of the galaxy, according to the astrophysicist.
Astronomers hypothesize that such collisions, which were hypothesized to exist, could occur routinely in such an environment. But this observation is very difficult because the hearts of galaxies are regions full of dust and gas.
