A group of researchers has determined that the Solar System survived a supernova that took place during the formation of the Sun. As they explain, it could have devastated our neighborhood, but a cloud of gas prevented it from becoming history before finishing its formation…
They have discovered it by studying the isotopes of elements discovered in meteorites. Remember that meteorites are fragments of asteroids. These, in turn, were formed from the material that was in the system when the Sun and planets formed. For this reason, these meteorites are fossils that, in essence, allow us to reconstruct how the evolution of the Solar System occurred.
Thus, researchers have found different concentrations of a radioactive aluminum isotope in meteorite samples. This has revealed that, around 4.6 billion years ago, there was an increase in radioactive aluminum in our environment. The best explanation for this injection of radioactive material is that a nearby supernova occurred. This is probably why the Solar System survived a supernova. The shell of material from the Solar System, surely, acted as a protective shield
Supernova explosions occur when massive stars reach the end of their lives and run out of fuel to fuse the elements within. At that point, the core is no longer able to avoid gravitational collapse. When it collapses, a supernova is triggered that spreads heavy elements, forged by the star throughout its life, and scatters them into space. That material will become the building blocks of the next generation of stars. But we cannot forget the power of a supernova.
The shock wave produced in the supernova, which carries this material with it, can be strong enough to tear apart any newborn planetary system that is close enough. Stars are born in huge clouds of molecular gas, which are made up of huge tendrils, or filaments. Smaller stellar objects, like the Sun, form in these filaments. The largest stars, like the one that must have exploded in that supernova, tend to form in places where those tendrils intersect.
With this in mind, the researchers have determined that it would take 300,000 years for the supernova shock wave to break through the dense shield of filaments that protected the young Solar System. Meteorites that are rich in radioactive isotopes broke away from larger objects, such as asteroids, that formed in the first 100,000 years of the Solar System’s life, when it was still in that dense filament. That shell must have acted as a protector of the Solar System against radiation.
Particularly important in this regard is the harsh radiation emitted by the hottest and most massive stars, called OB stars. Something that, had it not happened, would have negatively affected the formation of planets like Earth. The new results suggest that, in addition to acting as a shield, the filament was able to trap and channel radioactive isotopes, carrying them to the region around the young Sun. The researchers believe that this finding may be crucial to understanding the formation and evolution of stars and their planetary systems.
This scenario, the researchers explain, could have important implications for our understanding of the formation, evolution, and properties of star systems. For example, filaments could play an important role in protecting a young solar system. Thus, it protects it from far ultraviolet radiation, emitted by OB stars, which would be capable of evaporating the protostellar disk. This would affect the final size of the star and, in addition, it would also directly impact the formation of planets.
Beyond these considerations, it is important to take into account that the death of stars is an essential piece in the evolution of the universe. Each subsequent generation of stars incorporates the elements forged by the previous ones. Both in those less massive, such as the Sun, and those forged by supernovae (some as important as iron or phosphorus). So supernovae have an important role in both directions. On the one hand, they can be tremendously destructive, on the other, they are very positive.
The elements that they spread around them enrich the material from which the following stars will form. Our Sun, in this sense, is no exception, it incorporates in its interior elements that were forged by stars that died long before their formation. In other words, the Earth would not be a habitable (and inhabited) planet if it were not for all those elements forged in multitudes of generations of stars that lived, and died, long before the Sun even began its formation.