For the very first time, astronomers have captured a radio signal emitted by a very specific type of stellar explosion. This unprecedented observation offers us a glimpse into the final moments of a massive star, just before it transforms into a supernova.
Using the Very Large Array radio telescope located in New Mexico, a team monitored radio emissions for nearly a year and a half. These waves allowed them to reconstruct the star's activity in the decade leading up to its end, and more specifically its final five years of existence, marked by intense mass loss. Optical telescopes alone could not reveal these details.
Artist's impression of a supernova - M. Weiss
The studied star belongs to the category of Type Ibn supernovae. These events occur when a massive star ejects large amounts of helium-rich material shortly before exploding. The ejected gas also acts as a kind of cosmic mirror. When the supernova's shock wave hits this material, it generates powerful radio waves that provide additional information about the star's final moments.
The data collected before and at the moment of the explosion indicate that the star was likely part of a binary system, with another star orbiting it. The interactions between these two celestial bodies could have triggered the extreme mass loss observed just before the explosion. This hypothesis explains why the matter was ejected at such a high speed in the preceding years.
Until now, scientists relied mainly on visible light to study the end of stars. Now, radio observations open a new path for understanding these events throughout the Universe. This method allows us to look back in time and examine what happens more precisely.
According to the study published in
The Astrophysical Journal Letters, future research will extend this approach to other supernovae. The goal is to determine how frequently these mass loss episodes occur and what they teach us about the life cycle of massive stars.
Type Ibn supernovae
This category of stellar explosions is distinguished by the presence of helium in the materials ejected shortly before the star's end. This phenomenon is relatively rare compared to other types of supernovae, making each observation particularly valuable for astronomers.
Unlike classical supernovae, Type Ibn events involve massive stars that actively lose their outer envelope. This loss of matter creates a gaseous environment around the star, which directly influences the unfolding of the explosion. Studying these gases allows the star's history to be reconstructed over several years.
The recent discovery shows that radio observation can reveal details invisible in optical light.