SN2021yfj Reveals Star Stripped to Sulfur Layer Before 2021 Supernova

1 articles · Updated · Daily Kos · Jun 28

Spectra from SN2021yfj showed the star had already lost every outer layer before exploding in 2021, leaving material exposed down to its silicon-and-sulfur shell.
That makes it an “extremely stripped supernova,” a rare view into a massive star’s deep interior just before core collapse.
Standard stellar-wind models cannot explain such severe mass loss, because they are not strong enough to peel away layers that deep.
The finding gives theorists a new puzzle over what process removed the star’s envelope and intermediate layers before the blast.