A team of astronomers has observed a new type of supernova that provides an unparalleled glimpse into the internal structure of massive stars just before they explode. The study, published in the journal Nature, reveals that the star was stripped of its outer layers prior to the explosion and released a hidden layer of heavy elements.
According to the research, massive stars are structured like celestial onions, with lightweight elements such as hydrogen and helium at the surface. However, the team’s observations indicate that some stars can be stripped down to their core before exploding, revealing new insights into stellar evolution.
The discovery was made using data from the Zwicky Transient Facility at the Palomar Observatory in Southern California, which allowed the team to detect a rapidly increasing brightness signal 2.2 billion light-years away. The spectrum of the object revealed unusual features that suggested the presence of silicon, sulfur, and argon, which are not typically seen in dying stars.
“We’re seeing something new here,” said Adam Miller, assistant professor of physics and astronomy at Northwestern University. “This star lost most of its material throughout its lifetime, leaving behind only a shell of elements formed during the months leading up to its explosion.”
The team estimates that the star would have needed to release a massive amount of energy to shed its outer layers, releasing three times the mass of our sun over the course of its lifetime.
“This discovery is showing us that the zoo of astronomical transients is still not complete,” said Stefano Valenti, an associate professor in physics and astronomy at the University of California, Davis. “We need more examples like this to understand their nature.”
The team has designated the new supernova type as a Type Ien (pronounced one-e-n) supernova, which exposes deeper layers of the star than previously thought.
Scientists remain unsure about what triggered the star’s behavior, but the study suggests that it may have torn itself apart or interacted with a companion star. The discovery provides a unique opportunity to study massive stars and their internal structure.
As researchers continue to study this phenomenon, they are left wondering how often such explosions occur in the universe. “Did we happen to just get incredibly lucky?” asked Adam Miller.
Source: https://edition.cnn.com/2025/08/22/science/new-supernova-discovery