The Weizmann Institute of Science in Israel recently issued a statement saying that a team led by the institute and Northwestern University in the United States has discovered a new supernova rich in heavy elements such as silicon, sulfur and argon. Researchers have previously only observed the characteristics of light elements such as hydrogen and helium in some supernovae. The discovery helps scientists explore the deep internal structure of massive stars.
The team observed the supernova, numbered SN2021yfj, in an area about 2.2 billion light-years away from the Earth. Unlike previously observed supernovae, the spectral signal of SN2021yfj is characterized by the presence of large amounts of silicon, sulfur and argon. The team believes that this supernova may be the result of a massive star tearing itself apart, indicating that the star has lost its outer layer before the explosion, leaving only a deep "skeleton". This provides researchers with evidence to verify the "onion-like" layered structure of the star.
Massive stars have a layered structure, similar to that of an onion. The outermost layer consists mainly of the lightest elements; as the layers move inward, elements become heavier and heavier until they reach the very core. Supernovae are violent explosions that occur at the end of the evolution of massive stars. So far, only the signatures of light elements such as hydrogen and helium have been found.
According to the team, a star that is completely stripped to its deepest point can still produce such a dazzling explosion. This phenomenon may be related to the fact that the star experienced extremely violent material ejection before exploding: the star collapsed under its own gravity, and the core was further compressed and heated, triggering a violent nuclear fusion reaction and ejecting material rich in heavy elements. Multiple pieces of ejected material may even collide with each other, creating an exceptionally bright supernova explosion.
The statement said that the newly discovered supernova provides important clues to reveal the origin of heavy elements in the universe. Professor Gal Yam of the Weizmann Institute of Science believes that the inner layers of massive stars may be an important source of key elements such as silicon and sulfur.
Relevant research results have been published in the British magazine Nature.