Washington:
Researchers have discovered that the formation of the solar system was triggered by a low-mass supernova some 4.6 billion years ago. An Indian origin scientists is among the researchers involved in the new findings. A gas of gas and dust was disturbed about 4.6 billion years ago. Our solar system was eventually formed by the gas of gas and dust. According to researchers, the proto-Sun with a surrounding disc where the planets were born was formed by the ensuing gravitational collapse.
A supernova would have enough energy to compress such a gas cloud. A star exploding at the end of its life-cycle is known as supernova.
However, there was no conclusive evidence to support this theory.
The nature of the triggering supernova remained elusive. Short-lived nuclei present in the early solar system was the main focus of Professor Yong-Zhong Qian at University of Minnesota in the US and his collaborators.
The triggering supernova could have given birth to these nuclei because of their short lifetimes.
Their abundances in the early solar system have been inferred from their decay products in meteorites. As the debris from the formation of the solar system, meteorites are comparable to the leftover bricks and mortar in a construction site.
Researchers said they tell us what the solar system is made of and in particular, what short-lived nuclei the triggering supernova provided.
“This is the forensic evidence we need to help us explain how the solar system was formed. It points to a low-mass supernova as the trigger,” Qian said.
Qian and Projjwal Banerjee, postdoctoral research associate at University of Minnesota, realised that previous efforts in studying the formation of the solar system were focused on a high-mass supernova trigger, which would have left behind a set of nuclear fingerprints that are not present in the meteoric record.
Researchers decided to test whether a low-mass supernova, about 12 times heavier than our Sun, could explain the meteoritic record.
They examined Beryllium-10, a short-lived nucleus that has 4 protons and 6 neutrons, weighing 10 mass units. This nucleus is widely distributed in meteorites.
In fact the ubiquity of Beryllium-10 was something of a mystery in and of itself, researchers said.
Many researchers had theorised that spallation - a process where high-energy particles strip away protons or neutrons from a nucleus to form new nuclei - by cosmic rays was responsible for the Beryllium-10 found in meteorites.
Qian said that this hypothesis involves many uncertain inputs and presumes that Beryllium-10 cannot be made in supernovae.
Using new models of supernovae, the researchers have shown that Beryllium-10 can be produced by neutrino spallation in supernovae of both low and high masses. However, only a low-mass supernova triggering the formation of the solar system is consistent with the overall meteoritic record.
(With inputs from PTI)
