SN2021yfj showed unusually strong silicon, sulfur and argon signatures, giving astronomers a rare direct look at elements normally buried deep inside a massive star.
Those heavy-element lines indicate the star had been stripped almost down to its core before it exploded, making the event a previously unseen type of supernova.
Despite losing much of its outer layers, the star still produced an exceptionally bright blast visible from about 2.2 billion light-years away.
The observation offers an uncommon window into the internal layering of massive stars just before death, helping researchers probe how such stars evolve and explode.
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SN2021yfj: A Groundbreaking Supernova Exposes Stellar Core, Forces New Type Ien Classification, and Challenges Stellar Death Models
Overview
In 2021, astronomers observed SN2021yfj, a supernova that defied expectations and provided the first direct evidence of the deep inner layers of a massive star's core. This unique event offered an unprecedented glimpse into the final moments of a massive star, as its progenitor had already shed its outer layers of hydrogen, helium, and carbon well before the explosion. Just before its demise, the star expelled a hidden layer rich in silicon, sulfur, and argon, which was then illuminated by the supernova. SN2021yfj stands out as a first-of-its-kind discovery, reshaping our understanding of stellar evolution.