On February 23, 1987, a supernova explosion, visible with the naked eye, illuminated the night sky. This event gave astronomers a unique opportunity to study supernova explosions, because the previous explosion so close to the Earth occurred more than 400 years ago in 1604. However, astronomers in the recent past did not succeed in detecting either a neutron star or a black hole at the site of the explosion, which can be attributed to the imperfection of astronomical instruments of that time. And only recently, after more than 30 years, a neutron star generated by the 1987 explosion was found.
The supernova 1987A was visible to the naked eye due to the fact that the explosion occurred at a relatively short distance from us, at a distance of 168 thousand light years in the Large Magellanic Cloud, a dwarf galaxy that is a satellite of our Milky Way galaxy. The brightness of the 1987A supernova explosion flashed 100 million times the brightness of the Sun, and such an incredibly powerful source illuminated the night sky for several months. And even after the flash glow died out, astronomers continued for a long time and continue to study clouds of cosmic dust and gas, swept away by the explosion in the surrounding space.
When investigating the traces of the 1987A explosion, astronomers always had the same question. According to existing theories, an explosion of a star of such mass was supposed to leave behind a neutron star, an incredibly small, dense and hot space object, which is very difficult to miss from such a distance. However, the 1987A neutron explosion star has eluded detection for 32 years. Some astronomers have suggested that a neutron star is hiding behind a dense veil of cosmic dust, others that instead of a neutron star, a black hole or a quark star formed during the 1987A explosion, others said that all our theories are incorrect and the explosion left no trace clouds of dust and gas.
Now, scientists have managed to find the answer to the mystery 30 years ago. Researchers at Cardiff University said they managed to find a neutron star hidden in dense dust clouds. And this neutron star was discovered only thanks to the great capabilities of the ALMA radio telescope (Atacama Large Millimeter / submillimeter Array), located in Chile.
Astronomers noticed that one of the dust clouds in the explosion area of 1987A looks brighter in the submillimeter range and they immediately had a hunch about the cause of this anomaly, which is a neutron star.
“Despite the fact that all the light from a neutron star is absorbed by a dust cloud, it, this light, makes the cloud glow in the submillimeter range, which we see due to the high sensitivity of the ALMA telescope,” says Mikako Matsuura, a leading researcher.
The detection of a neutron star remaining after the 1987A explosion is of very important scientific importance. It serves as a confirmation that all existing theories regarding supernova explosions are correct. And in the future, the light of a neutron star will be scattered by the surrounding cloud and this star can be studied in more detail.