DATE2025.09.03 #Press Releases
Turbulent Interior of a Dying Star
Disclaimer: machine translated by DeepL which may contain errors.
-- Revealing Violent Pre-Supernova Nuclear Burning from a Supernova Remnant --
Summary
An international research team, including Dr. Toshinori Sato (Assistant Professor, Department of Physics, School of Science and Technology, Meiji University), Yui Kuboike (1st-year Master’s student, Department of Physics, Graduate School of Science and Technology, Meiji University), Associate Professor Hideyuki Umeda (School of Science, The University of Tokyo), Kai Matsunaga (2nd-year Doctoral student, Department of Physics and Astronomy, Graduate School of Science, Kyoto University; Research Fellow of the Japan Society for the Promotion of Science), Assistant Professor Hiroyuki Uchida, and Dr. Takashi Yoshida (International Program Coordinator, Yukawa Institute for Theoretical Physics, Kyoto University), has discovered evidence that the internal structure of a massive star was destroyed by intense nuclear burning in the final few hours before its core-collapse supernova explosion.
This result was obtained through X-ray observations of the supernova remnant Cassiopeia A (see figure). While the lifetime of a massive star is thought to span several million to tens of millions of years, its internal structure undergoes dramatic changes driven by violent nuclear burning during the final months to hours of its life. However, such internal evolutionary processes cannot be directly observed from living stars. By analyzing the elemental information preserved in a supernova remnant more than 300 years after the explosion, the research team has established a novel method to trace back the "final memories" of the star’s lifetime.
These findings were published in the Astrophysical Journal on September 2, 2025.
X-ray image of Cassiopeia A observed by the Chandra satellite
(Red: oxygen, Green: magnesium, Blue: silicon).
The differences in the mixing of the three colors are believed to have been formed during the intense nuclear burning processes in the progenitor star immediately prior to the explosion.
Related Links
Meiji University, Kyoto University
Journals
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Journal Name The Astrophysical JournalTitle of paper Inhomogeneous Stellar Mixing in the Final Hours before the Cassiopeia A Supernova