This was a core collapse supernova. “For the first time we watched a red supergiant explode! The activity of such a giant star has never been followed before it explodes in a Type II supernova, ”says Jacobson-Galán. On the basis of the numerous data, the working group was able to determine that the supergiant was around 5000 Kelvin hot before its end and encompassed 1500 times the radius of our sun. In addition, it was ten times more massive than our central star.
Amazingly, the dying star was still extremely active before its finale, releasing enormous amounts of radiation and matter. Jacobson-Galán and Co. wrote that it was the first type II supernova for which such a high level of activity was observed. Otherwise, the moments before the corresponding supernovae were much quieter. At least some supergiants are behaving differently from what was previously noticed.
Strong changes in the internal structure of the star, which caused a sudden supply of energy to the shell, are probably responsible for this. It then led to increased output of stellar material, which was ultimately observed. How this energy supply came about is, however, unclear. Gravitational waves from the fusion of neon and oxygen or a nuclear flash from the combustion of silicon could be considered. But these are still hypotheses, write the astronomers.