Astronomers observed a supernova, designated 2021yfj, which provided a rare glimpse into a star's interior by revealing a silicon- and sulfur-rich layer, confirming longstanding theories about layered stellar structures before explosion.

This discovery supports models suggesting that massive stars end their lives with layered structures, with lighter elements on the outside and heavier elements near the core.

The supernova's unusual elemental composition indicates the star experienced a highly violent internal event, possibly involving internal self-stripping or core re-ignition of nuclear fusion, leading to the expulsion of outer layers.

Published in the journal Nature, this finding offers valuable insights into the final stages of stellar evolution, although capturing such an event again may be challenging.

It remains uncertain whether the star lost its outer layers through violent ejections in its final stages or via interaction with a binary companion, with future research expected to shed more light on the process.

The findings suggest that the star's outer layers could have been ejected through shell collisions, multiple eruptions, or interactions with an unseen companion, but the exact mechanism remains unclear.

The discovery, made possible by advanced telescopes like the W.M. Keck Observatory, contributes significantly to understanding the final phases of massive star life cycles.

This research challenges existing models of stellar evolution, indicating that massive stars may end their lives through more complex and exotic pathways than previously thought.

The presence of helium in the supernova's spectrum is puzzling because it should have been consumed earlier, suggesting unusual stellar processes at play.

Researchers hypothesize that core collapse and densification may have reignited fusion reactions, causing explosive episodes that ejected the star's outer shells.

This star had lost an unprecedented amount of its layers, providing new evidence about the processes involved in star death and the extent of stellar stripping.

Spectroscopic analysis revealed the presence of rare elements like silicon, sulfur, and argon moving at high speeds, indicating these elements originated from deep within the star.

The ejection of outer layers and subsequent collision of expelled material may have triggered the supernova's bright glow, highlighting complex internal interactions.