Ancient Supernova Explosion Almost Destroyed Our Infant Solar System, Study Suggests

A supernova explosion close to our Sun at the dawn of its formation could have destroyed our Solar System without a molecular gas barrier.

Evidence from Meteorite Samples

A group of researchers led by astrophysicist Doris Arzoumanian from the National Astronomical Observatory of Japan studied isotopes of elements present in meteorites. These chunks of rocks were pieces of asteroids from material current when the Sun and the planets began forming. Because of this, the meteorites serve as fossils that provide information for reconstructing the evolution of the Solar System.

Upon investigating meteorite samples, Arzoumanian and his colleagues discovered different concentrations of radioactive isotope of aluminum. This means an additional amount of radioactive aluminum entered our planetary neighborhood around 4.6 billion years ago.

According to the research team members, a nearby supernova blast is the best explanation for infusing radioactive material. These findings concluded that our infant Solar System possibly survived a blast wave with its birth cocoon acting as the buffer.

Surviving a Supernova Blast Wave

Massive stars exist by burning a tremendous amount of nuclear fuel at their cores. This fuel produces tons of energy, making the star's center very hot. The pressure generated by the heat keeps the burning star from collapsing.

A supernova explosion happens when a massive star has reached the end of its life. Since it runs out of fuel for nuclear fusion, its core cannot support itself against gravitational collapse. As the dying star's core explodes, the heavy elements it forged throughout its lifetime are spread into space.

The scattered material becomes the building blocks of the next generation of stars. However, the blast wave that delivered it outward can be sorted so that a neighboring planetary system starting to form can be ripped apart.

Stars are formed in giant clouds of molecular gas made of dense tendrils or filaments. Smaller stellar objects like our own Sun are born along these filaments, while larger stars that can explode into a supernova are formed at the regions where these filaments intersect. The research team estimated that around 300,000 years is needed for the supernova shockwave to destroy the dense filaments that shield the infant Solar System.

Meteorites full of radioactive isotopes split apart from larger objects, such as asteroids created in the first 100,000 years of our Solar System while it was in the dense filament. The birth cocoon could have protected the emerging planetary system from the harsh radiation released from hot and massive stars called OB stars.

The result of the study suggests that aside from being a shield, the filament could have collected and spread radioactive isotopes, channeling them into the region around the forming Sun. Arzoumanian and his team are confident that the findings of their investigation can have multiple important implications in understanding the formation and evolution of stars and their planetary systems.