General, Research, Technology

A neutron star that has been searched for over 30 years may have been discovered

The densest objects in the universe are neutronstars - collapse into the most mysterious - black holes. However, these metamorphoses are preceded by a phenomenon characteristic of massive stars - supernova explosions. So, for 30 years, scientists hunted for the most famous supernova in recent history. On February 23, 1987, astronomers watched reverently as a star exploded in a neighboring galaxy - it was the closest supernova explosion to our planet in 400 years. Both professionals and amateur astronomers around the world immediately directed their telescopes to a dying star, expecting to see the birth of a new object - a neutron star. But all their searches did not lead to anything, leaving the experts disappointed and puzzled. Only recently there was information that astronomers were able to detect clear evidence of a “missing” neutron star, which is hiding in a still-cooling starry debris from a supernova explosion. This gives scientists a unique opportunity to study the processes that occurred before and after the catastrophic death of a star.

In the center of the image are the remnants of supernova SN 1987A

Studying Stardust

In an article published in the journal AstrophysicalJournal, a team led by Phil Chigan of Cardiff University in the UK, peered into stardust to see a neutron star. One of the key obstacles to the study of the supernova, which was called SN 1987A, is that it left behind a huge curtain of dust, which makes up about half the mass of our Sun, hiding the place where there was once a star. But, analyzing archival data for 2015 collected by the ALMA telescope in Chile, the team found dust emissions indicating that there was something hidden inside.

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Supernova SN 1987A is located in 163 thousandlight years from Earth in the dwarf galaxy of the Large Magellanic Cloud. The final results of supernova explosions are the densest of known astrophysical objects: neutron stars that compress several solar masses into a ball the size of a city, and the discarded material around it grows into wriggling, majestic threads. SN 1987A is no exception. So around it you can see bright and beautiful eccentric dust rings that glow from the pulsating shock waves. In addition, SN 1987A is unique in its proximity to Earth. Prior to this explosion, experts had never observed a progenitor star in such detail. Even before this supernova became famous, astronomers knew that its mass is about 20 times the mass of our Sun and that size is likely to lead to the formation of a neutron star. However, the lack of direct detection of an object, despite attempts to see it with the best telescopes in the world, made some researchers think about whether the theoretical models of supernovae were wrong, and whether any other process had occurred on outer space.

On the left is a supernova flash, on the right are the remnants of an explosion shrouded in dust

How to see a hidden star?

Unable to see a neutron stardirectly inside its cocoon-like accumulation of gas, no one can prove that this object is a neutron star, and not a mirage of dense dust. Astronomers hope that in the coming years and decades dust will begin to disperse, allowing them to first look into the center, but even this remains inaccurate. Researchers plan to continue observing the SN 1987A in 2020 with the Hubble Space Telescope. By the way, we recently told you that a supernova collapsed into a black hole right in front of its lens. Despite the fact that so far no one has managed to make out the neutron star, the interest in SN 1987A is unlikely to come to naught soon. Note that today, scientists are observing a large number of supernova explosions that occur every year very far from Earth. While the SN 1987A is the only supernova we see in real time. So let's hope that the researchers are finally lucky.