Astronomers have seen evidence for the first time that a star has exploded twice. Exploding stars are not new, but the fact that the same star can explode twice has not yet been established. The researchers speak of the “most important explosions in the universe.”
It concerns a so-called type 1a supernova. A supernova is a large star that explodes. In a type 1a, there are actually two stars that together form one whole, a so-called binary star. By studying the remnant of supernova SNR 0509-67.5 at a distance of approximately 160,000 light-years, scientists saw that the same star can explode twice.
The first explosion was caused by an outer ‘shell’ of helium becoming unstable. In this case, that caused the first explosion on the surface of the star. According to the astronomers, that explosion also sent strong shock waves to the core of the star. As a result, it was compressed to the point that another explosion took place.
Type 1a supernovae are the most important source for the element iron. According to the researchers, those supernovae make more than half of all the iron in the universe. “Yet we still don’t understand exactly how that process works, even though they are so important.”
The scientists therefore speak of “the most important explosions in our universe.” According to the researchers, it indicates that stars can explode before they burn out and collapse under their own mass. In addition, according to principal investigator Priyam Das, the explosions “just look really cool.”