Scientists have confirmed what happened to a star that was born more than thirty years ago in a stunning supernova visible from Earth: it transformed into a neutron star, one of the world's largest objects and the strangest in the universe.
Posted at 9:12 am
Seth Borenstein Associated Press
In 1987, a star in a nearby galaxy exploded in a supernova, and its fiery end was visible to the naked eye in Earth's night sky for months. Scientists assumed that when the star's core collapsed, the remnants would turn into one of two things: a black hole, from which nothing escapes, or a neutron star, the densest object 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 got to the heart of the matter by looking into infrared light and detecting two telltale chemical signatures – argon and sulfur – of a superhot pulsating neutron star, according to a study published Thursday in the journal Science.
Because the explosion is new and well-documented, this discovery should help astronomers better understand this type of cosmic oddity and its predecessors, which helped fertilize the universe with important elements like carbon and iron.
This neutron star measures just 20 kilometers from end to end, but weighs one and a half times as much as our Sun. It is very dense and has little space between the different parts of its atoms. According to scientists, supernova 1987A is probably the only time that modern astronomy has been able to observe the birth and early years of a neutron star, although there are other, closer but older stars in our galaxy.
“Next to 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 any of them actually form. ยป
Images of the distant supernova remnant show what Fransson calls “a ring of pearls” surrounding a cloud of dust. 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 from the Webb telescope provides a fairly clear answer, even if it is not a direct image of the neutron star, according to Mr. Fransson and other scientists.
Roger Blandford, an astrophysicist at Stanford University who was not involved in the study, believes the neutron star case is sound.
Because the supernova explosion is so young and so close, it is “a gift that continues to teach us about neutrinos, the evolution of stars and what happens after the explosion,” Blandford said in an email.