A team of astronomers was able to observe the death of a red supergiant star for the first time. After the explosion, the star turned into a supernova – a star whose luminosity increases many million times after the eruption. The research was published in the Astrophysical Journal, and the observation gave the scientific community an unprecedented look at how a red supergiant turns into a supernova.
Scientists had been observing the red giant star from the NGC 5731 galaxy for 130 days before it exploded. Located at a distance of about 120 million light-years from Earth and having a mass of about 10-12 solar masses, the red giant star was first discovered in the summer of 2020, thanks to the light it emitted. In autumn, scientists recorded a bright explosion.
Red supergiant stars are the largest of the stars, whose life cycle ends with a supernova explosion. Before the new discovery, it was assumed that the transition to a supernova occurred relatively smoothly. Past data did not reveal any abrupt changes in the structure of a red supergiant that would precede the explosion.
However, new research shows the opposite. At least some of the red supergiant stars undergo great structural changes before they turn into supernova stars.
Now scientists can look for bright radiation from red supergiant stars that could signal their death, and examine the stars in detail before they explode.