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Astronomers believe they have discovered the remnants of a neutron star left by supernova 1987A



When the sky in the southern hemisphere was lit in February 1987, it was the brightest supernova in nearly 400 years. The 1987A supernova-the explosion of a blue super-giant star called the Super Magellanic Cloud in the nearby Mini Milky Way-surprised the astronomy community. It provides them with an unprecedented opportunity to observe an exploding star in real time using modern instruments and telescopes. But something is missing. After the supernova decay, astronomers expect to find a leftover neutron star (a high-density, collapsed stellar core composed mainly of neutrons) at the center of the explosion. They saw nothing.

For the next 34 years, astronomers have been searching for the missing neutron star, but without success. Various theories have emerged. Maybe there is no time to form yet. Perhaps the mass of the blue supergiant is greater than expected, and the supernova produced black holes instead of neutron stars. Maybe the neutron star is hidden, covered by exploding dust. If there is no star at all, it is really hard to see.

But perseverance pays off. Astronomers may finally find it.

The first hint came from the Atacama Large Millimeter/Submillimeter Array (ALMA) in Chile last summer. The radio telescope observed a hot “spot”

; inside the supernova core. The “spots” themselves are not neutron stars, but heated clumps of dust and gas, which may hide neutron stars in them: after all, there is something providing heat. But to confirm the existence of neutron stars, further observation is needed.

Armed with the encouraging radio signal results from ALMA, a team of researchers then used data from two different NASA spacecraft to observe supernovae at X-ray wavelengths: the Chandra X-ray Observatory and the Nuclear Spectroscopy Telescope Array (NuSTAR). Their results will be published in the Astrophysical Journal this month. What they discovered was the X-ray emission near the core of the supernova explosion. There are two possible explanations.

Supernova 1987A, with a pulsar nebula in the center. Image source: Chandra (X-ray): NASA / CXC / Univ. Di Palermo/E. Greek illustration: INAF-Osservatorio
Palermo Astronomer/El Orlando

First, the emission may be the result of particles being accelerated by the shock wave of the explosion. This shock wave theory cannot be completely ruled out, but the evidence seems to point to another more likely explanation-the pulsar nebula.

A pulsar is a fast-rotating high-energy neutron star that emits radiation outwards like a beacon when rotating. Pulsars sometimes produce high-speed winds that blow outward and create nebulae that are affected by charged particles and magnetic fields. The researchers think this is what they see.

Chandra and NuSTAR data have supported ALMA testing since last year. There is a young pulsar somewhere in the center of supernova 1987A. It may take a decade or more for the supernova nucleus to be cleared to observe the pulsar directly, but for the first time in 30 years, astronomers can be confident that it exists.

Supernova 1987A seen by NuSTAR and Chandra. Image source: Chandra (X-ray): NASA/CXC/University. Palermo/E. Greek; Illustration: INAF-Palermo Observatory/Orlando Savior; NuSTAR (X-ray): NASA/JPL-CalTech

This discovery is exciting. One of the researchers involved in the exploration, Salvatore Orlando (Salvatore Orlando) said: “In essence, it is unprecedented to be able to view a pulsar from the day it was born. “It may be a once-in-a-lifetime study of the development of baby pulsars. Opportunity. “

Therefore, having solved the 30-year-old mystery and a large amount of new scientific work in the coming decades and even decades, Supernova 1987A is expected to attract our attention. After all, this is the closest and brightest supernova we have ever seen.

Unless Betelgeuse explodes…

(Betel nut is unlikely to explode soon)

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