(ORDO NEWS) — A powerful event that likely predated the formation of our solar system is solving a long-standing mystery of meteorites.
The stuff that made up our solar system was dispersed when the shock wave from an exploding supernova blasted the material into a cloud of dust and gas, causing it to collapse.
After this event, most of the ejected matter was gravitationally drawn into the center of the vortex, where, due to an intense increase in pressure, nuclear fusion began, and the Sun was born.
The young star was surrounded by a spinning disk of leftover gas and dust from which the planets and other bodies of the solar system were formed – some of which eventually broke apart to form asteroids and meteorites.
“The mystery comes from studying the isotopic composition of meteorites, which can be used as a laboratory to test theories of the formation and evolution of the solar system,” explains Carnegie’s Alan Boss.
He added: “Because we know exactly how long this process takes for various radioactive isotopes, measuring the amount of progeny in meteorites can tell us when and possibly how they formed.”
For example, an isotope of iron with an atomic weight of 60 is produced in significant quantities only in a supernova explosion, and it takes 2.6 million years for half of the atoms to decay – the so-called “half-life” – into a daughter isotope, cobalt-60.
So when significant amounts of cobalt-60 are found in primitive meteorites called carbonaceous chondrites, it tells researchers that the raw materials from which the chondrite was built contained the remnants of a supernova explosion that occurred just a couple of million years before it formed.
Chondrite data can be used to confirm the version of the origin of our solar system from a supernova. But other, less primitive, non-carbon meteorites don’t have this iron-60 composition, which means the material they formed from didn’t come from a stellar explosion. So where did he come from?
“No physical explanation for this dramatic change has been offered,” says Boss.
The shock front of a supernova sweeps interstellar dust out of the formed disk and accelerates the formed protostar to a speed of several kilometers per second. This is enough for the young sun to collide with a new patch of interstellar matter depleted in iron-60 and other isotopes formed by a supernova within a million years.
“After we had been working on the problem of supernova launch and injection since the mid-90s, it was amazing that we were finally able to connect this model to meteorite data,” concluded Boss. “She ends the story with a neat bow.”
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