Several of the astronomical phenomena in our universe that are yet to be explained are deeply related to “binary star systems.” Binary stars are “twin stars” that evolve by influencing each other, including exchanging mass. This phenomenon, known as “binary star evolution,” is closely related to phenomena that are important for understanding the beginning and evolution of the universe, such as supernova explosions and gravitational wave radiation. Therefore, gaining an understanding of the effect of binary star systems on stellar evolution plays an important role in unraveling the mysteries of the universe.
No systematic research into binary star systems, defined as “supernova progenitors” that are extremely massive and ultimately undergo a supernova (e.g., white dwarfs and red supergiants) has been conducted thus far.

Associate Professor Kinugawa and his team conducted the world's first systematic investigation into the impact of the interactions in binary star systems on the evolution of supernova progenitors.
They simulated and reproduced the evolutionary process of a supernova progenitor in a binary star system on a computer and identified the types of supernova explosions that will occur at the end of this evolution. These supernova explosions were categorized it into six types, such as Type Ibc supernova (the explosion of a star that has lost its hydrogen envelope) and Type II supernova (the explosion of a star with a hydrogen envelope). In addition, the incidence of each type of supernova was also estimated.
These results were consistent with those of existing observational studies.

The effect of binary star systems on the evolution of stars in supernova progenitors has not been systematically studied thus far. Therefore, the findings of this study may be a major step toward clarifying the impact of binary star systems on the evolution of stars. Supernovae also have a major impact on other astronomical phenomena. Thus, gaining an understanding of supernovae could potentially contribute to unraveling the mysteries of the universe.
Associate Professor Kinugawa and his team are proceeding to the next step: attempting to clarify the influence of binary star systems on the evolution of the “first stars” born in the early universe and supernova explosions of low-metallicity stars. The further back in time we go, the closer we are to unlocking the mystery of the early universe. Thus, the findings of this study are likely to attract a lot of attention.