Scientists can finally show that a neutron star formed from our most well-studied supernova, SN 1987A. The breakthrough was made possible thanks to the James Webb telescope.
Supernovae are the spectacular end result of the collapse of stars more massive than 8-10 times the mass of the sun. Besides being the main sources of chemical elements such as carbon, oxygen, silicon, and iron that make life possible, they are also responsible for creating the most exotic objects in the universe, neutron stars and black holes.
In 1987, supernova 1987A (SN 1987A) exploded in the Large Magellanic Cloud, which is located near the Milky Way. It was the first time in four centuries that a supernova became visible to the naked eye, giving astronomers an unprecedented close-up of a supernova explosion. Although SN 1987A is one of the most studied objects in the sky, the question of what was left after the explosion remains unanswered. Did it become a compact neutron star or a black hole? The detection of neutrinos, which are produced in the supernova, indicated that a super compact neutron star should have formed at the center of the SN 1987A. But even after three and a half decades of intensive observations with the best telescopes, no conclusive evidence of such a neutron star has been found, until now.
In a study published on February 22 in the journal Science, an international team of astronomers announced that they had detected signals from a neutron star from the centre of the nebula around SN 1987A. Using the James Webb Telescope (JWST), the authors were able to observe spectral lines that had either been created from the hot neutron star or from a so-called pulsar wind nebula around the neutron star.
"Thanks to the fantastic resolution and the new instruments at JWST, we have been able to examine the centre of the supernova and what was created after the explosion for the first time. We now know that there is a compact source of ionizing radiation there, which is likely a neutron star. This was predicted by the explosion models and we did simulations in 1992 that indicated how to observe this, but it was only with JWST that it became possible. However, the details offered several surprises," says Claes Fransson, professor at the Department of Astronomy, Stockholm University and the Oskar Klein Centre and the lead author of the study.
"This is the latest in a series of surprises that this supernova has offered over the years. It was unexpected that the compact object would finally be detected through a very strong argon line, so it was a bit fun that it turned out this way," says Josefin Larsson, professor at the Department of Physics, KTH Royal Institute of Technology and the Oskar Klein Centre and co-author of the study.
Read article in Science: Emission lines due to ionizing radiation from a compact object in the remnant of Supernova 1987A DOI: 10.1126/science.adj5796
