The observation of the explosion of the supernova SN 1987A is one of the most significant astronomical events of the XXe century. Researchers continue to study it. And they show today that it was probably the result of the explosion of a blue supergiant born from the fusion of two stars.
SN1987A: the accelerated explosion of the famous supernova for 30 years At a rate of 4 years per second, this NASA ehealth shows the explosion of the supernova discovered in 1987 and followed for 30 years. Considering the distance, these events occurred 168,000 years ago. The dying star first expelled the ring of matter (shown in red). 20,000 later, it exploded: it was the flash observed in 1987. The material ejected at high speed, followed by a telescope, now strikes the ring. This shock wave heats the material, which has become very bright.
In February 1987, astronomers witnessed the explosion of a star in the Large Magellanic Cloud, a galaxy neighbor of our Milky Way, one of the most important astronomical events of the XXe century. Today, researchers from Riken University (Japan) suggest that this supernova – baptized SN 1987A – could have been born from the explosion of a supergiant blue formed by fusion of two stars.
Remember that the supernova SN 1987A formed by what astronomers call a collapse of heart. This is what happens when the nucleus of a massive star can no longer resist its own gravity. Her heart then collapses to form a star neutron or to a black hole even as a violent explosion sweeps away the outer layers of the star.
They are generally stars of type red supergiant that produce this kind of supernova. But past observations have already shown that thebirth star from SN 1987A is a blue supergiant. Observations that researchers are struggling to explain.
A simulation faithful to the observations
What astronomers' theories do not explain, in particular, are clusters of nickel radioactive observed at X-rays and to gamma rays in the matter ejected by the supernova. This nickel formed at the heart of the star, when it collapsed. He walks away at a speed over 4,000 kilometers per second.
The fusion of a red supergiant and a star of the main sequence
Simulations by researchers at Riken University show that the scenario that comes closest to observations is as follows: the SN 1987A supernova is the result of the explosion of a blue supergiant formed by the fusion of two stars and more exactly a red supergiant and a main sequence star.
Astronomers detail that, during the fusion, the largest star would have stripped its companion of its matter. This would have been absorbed in a spiral to then form a rapidly rotating blue supergiant, which would then have itself ended its life in a so-called supernova explosion asymmetric. A mechanism which seems to reproduce with precision the clusters of nickel observed.
Researchers at Riken University say this work could also help locate theneutron star born of the cataclysm. It would be to seek in the northern part of the interior region of material ejected. A region in which the asymmetrical explosion, which hit the blue supergiant, could have projected it.
What you must remember
- A red supergiant and a star from the main sequence that merge to form a blue supergiant.
- Blue supergiant whose models suggest today that it was the precursor of the 1987 SN A supernova.
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