Researchers from ETH Zürich have announced they have been able to date events in the early solar system with greater precision than ever before possible using an extinct atom called niobium-92. The atom has a half-life of 37 million years, which is considered to be relatively brief leading to its extinction shortly after forming the solar system.
Researchers on the study say if an atom of a chemical element has a surplus of protons and neutrons, it becomes unstable. The additional particles are shed as gamma radiation until the element becomes stable again. Niobium-92 was one such unstable isotope, also known as a radionuclide.
Today the only way scientists know niobium-92 existed is because of its stable daughter isotope zirconium-92. While niobium-92 is extinct, scientists have made use of the radionuclide in the form of a niobium-92-zirconium-92 chronometer used to date events that took place in the early solar system 4.57 billion years in the past. The chronometer’s use has been limited in the past by a lack of precise information regarding the amount of niobium-92 present when the solar system was born.
The lack of that information compromised the ability of scientists to use the chronometer for dating and determining the production of radionuclides in the solar system. The researchers from ETH Zürich, working with scientists from the Tokyo Institute of Technology, have greatly improved the chronometer by recovering rare zircon and rutile minerals from meteorite remains of a proto-planet called Vesta.
The team used a uranium-lead dating technique to calculate how abundant niobium-92 was at the solar system’s formation. Armed with more precise knowledge about how abundant niobium-92 at the beginning of the solar system allowed scientists to determine more accurately where the atoms formed and where the material that makes up the sun and planets in our solar system originated.
The new model suggests that the inner solar system with the terrestrial planets Earth and Mars is primarily made up of ejected material from a type Ia supernova that occurred in the Milky Way galaxy. The outer solar system was likely formed primarily by a core-collapse supernova, likely in the same stellar nursery where the sun was born.