Overview

• A Nature study of SN2021yfj reports a star that had shed nearly all exterior material, exposing gas rich in silicon, sulfur and argon.
• The transient was flagged by the Zwicky Transient Facility, and an unexpected spectrum from a UC Berkeley collaborator enabled swift Keck follow-up.
• The observations provide a direct view of a dying star’s inner structure, supporting theories of layered nuclear burning and element production.
• The team proposes a new supernova classification, Type Ien, while the process that caused the extreme stripping remains unresolved.
• Reports conflict on the event’s distance and host, with some articles citing a Milky Way location and others about 2.2 billion light-years away.