Around 4.6 billion years ago, the gravitational collapse of a cloud of gas and dust triggered the formation of our Solar System. Now, new research has shown what triggered this collapse: a low-mass supernova.
Prior to this study, astronomers had already predicted that a supernova (an exploding star) had caused the initial collapse, creating a disturbance that led to the creation of the proto-Sun and surrounding protoplanetary disc. But the exact nature of the supernova remained a mystery.
The international team of scientists used new computer models and meteorite composition analysis to make their breakthrough. In particular, they looked for the ‘nuclear fingerprint’ of the supernova. Supernovas release short-lived radioactive nuclei that break down to form decay products, which can be detected in meteorites to this day. Each type of supernova produces different nuclei, resulting in an individual fingerprint.
The team, led by Prof Yong-Zhong Qian at the University of Minnesota, identified three main isotopes within the meteorite: beryllium-10, calcium-41 and palladium-107. This combination of isotopes matches the nuclear fingerprint for a low-mass supernova, which kick-started the birth of our solar neighbourhood.