Scientists have confirmed what happened to a star that gave birth in a stunning supernova visible from Earth more than thirty years ago: it transformed into a neutron star, one of the world’s largest objects. strangest in the universe.
In 1987, a star in a nearby galaxy exploded in a supernova, and its fiery end was detected by the naked eye in Earth’s night sky for months. Scientists believed that when the star’s core collapsed, the remains would turn into one of two things: a black hole, from which nothing escapes, or a neutron star, the object the densest in the universe outside of a black hole.
The problem was that there was so much debris that astronomers couldn’t see past the dust. But NASA’s Webb Space Telescope cut to the chase by peering into infrared light and detected two telltale chemical signatures ― argon and sulfur ― of a super-hot pulsing neutron star, a study suggests published Thursday in the journal Science.
Because the explosion is recent and well-documented, this discovery should help astronomers better understand this type of cosmic oddity and its predecessors that helped seed the universe with important elements such as carbon and iron.
This neutron star measures only 20 kilometers from one end to the other, but weighs one and a half times our sun. It is very dense, with little space between the different parts of its atoms. According to scientists, supernova 1987A is probably the only time modern astronomy has been able to observe the birth and early years of a neutron star, although there are others, closer but older, in our galaxy.
“Besides the black hole, these are the most exotic objects in the universe,” said lead author Claes Fransson, an astrophysicist at Stockholm University, Sweden. We’ve known about these objects since the 1960s, but we’ve never seen one of them actually form. »
Images of the distant supernova remnant show what Fransson calls “a ring of pearls” surrounding a dust cloud. Somewhere in the middle of this dust is the neutron star.
Scientists had long suspected that the collapsed core had become a neutron star. But this measurement made by the Webb telescope, even if it is not a direct image of the neutron star, provides a fairly definitive answer, according to Mr. Fransson and other scientists.
Roger Blandford, an astrophysicist at Stanford University who was not involved in the study, believes the arguments for the neutron star are well-founded.
With the supernova explosion so recent and so close, it’s “a gift that keeps on giving, teaching us things about neutrinos, the evolution of stars and now what happens after the explosion,” Mr. Blandford said in an email.