An exploding star has given researchers a rare chance to find out what the inside of old stars looks like, according to an international study.
Usually, when a star explodes in a supernova, the internal layers get mixed up, making it hard to determine its structure. However, in 2021, a star called 2021yfj exploded after having already lost most of its outer layers, giving the researchers a chance to see just what it looked like on the inside.
They found a thick, massive silicon- and sulphur-rich shell which was expelled by the star shortly before the supernova explosion. However, they also detect helium, which was surprising as it was assumed that this lighter element would have been lost during earlier stages of the supernova.
Writing in an accompanying News & Views, Anya Nugent and Peter Nugent say that the discovery “…provides direct confirmation that stars have the theoretically predicted shell structure all the way down to their silicon- and sulfur-rich layers.” They add that the findings uncover “…mysteries about how massive stars end their lives.”