Astronomers managed to get rare glimpse inside dying star while exploding

For the first time, scientists have captured a rare glimpse inside a dying star as it exploded, providing new insights into the life cycle of massive stars. The discovery of supernova 2021yfj was possible only because several rare factors aligned. A supernova is a short-lived, luminous event triggered when a star ends its life in a massive explosion. Astronomers detected 2021yfj shortly after it erupted, revealing something unprecedented—a layer rich in silicon and sulfur, long theorized to encase the cores of massive stars.

The breakthrough, published on August 20 in Nature, came from the study of supernova 2021yfj in the Milky Way galaxy. What makes this observation unique is that the explosion exposed the inner layers of the star in a way astronomers had never seen before. 

Stars live for millions to trillions of years, burning fuel until they reach the end of their life. The largest stars end in spectacular explosions called supernovas, which release immense energy and scatter stellar material across the cosmos.

Typically, when a supernova occurs, the violent blast mixes the star’s layers, making it nearly impossible to distinguish its internal structure. However, this event allowed researchers to confirm long-held theories about stellar composition: stars are layered like onions, with lighter elements such as hydrogen and helium on the outside and heavier elements like silicon and sulfur deeper inside.

“This is the first time we have observed a star stripped to this extent,” said Steve Schulze of Northwestern University, part of the discovery team. The finding confirmed that the star’s outer hydrogen and helium layers had been removed long before the explosion—a common phenomenon—but surprisingly, its dense inner layers of silicon and sulfur were also shed during the blast.

“This basically confirmed what those layers were,” explained Anya Nugent of the Harvard-Smithsonian Center for Astrophysics, who was not involved in the research. This observation strengthens scientific models of how massive stars evolve and die, but it also raises new questions.

The report notes, however, that one key mystery is how the star became so stripped. Researchers suspect either a violent ejection during its final evolutionary stages or gravitational interaction with a companion star. Determining the exact mechanism will require more observations, though scientists acknowledge that witnessing a similar event again could be extremely difficult due to its rarity.

By Nazrin Sadigova