Duration of solar system formation identified
The material that makes up the Sun and the rest of the Solar System came from the collapse of a large cloud of gas and dust. And whereas astronomers have observed distant stellar systems that formed similarly to ours estimate that it probably takes about 1-2 million years for the collapse of a cloud into an ignited star, this is the first study able to provide age constraints on formation of our own Solar System. Our solar system is over 4.5 billion years old, and it was formed in less than 200,000 years, according to an international research team led by planetologists from the University of Münster. The results of the study have been published in the journal “Science”.
Background and methodology
The first solids to form in the Solar System—micrometer- to centimeter-sized inclusions in meteorites called calcium-aluminum–rich inclusions (CAIs)—provide a direct record of Solar System formation. The majority of CAIs formed 4.567 billion years ago, over a period of about 40,000 to 200,000 years. “Since the observed time span of stellar accretion (1-2 million years) is much longer than CAIs took to form, it raised the question of which astronomical phase in the Solar System’s formation is recorded by the formation of CAIs, and ultimately, how quickly was the material that makes up the Solar System accreted”, says cosmochemist Dr. Greg Brennecka from Lawrence Livermore National Laboratory in California, who previously worked at Münster University in the group of Prof. Dr. Thorsten Kleine. The study shows that the vast majority of material that formed the Sun and Solar System accreted quickly during the same time its oldest dated solids were forming, which we know lasted less than 200,000 years.
The research team measured the molybdenum (Mo) isotopic and trace element compositions of a variety of CAIs taken from carbonaceous chondrite meteorites. “We found that the distinct Mo isotopic compositions of CAIs cover essentially the entire range of material from the protoplanetary disk. In other words, CAIs potentially record the entire history of infall from the molecular cloud to the Sun”, explains Thorsten Kleine of the Institute for Planetology. And since scientists know when and how long it took CAIs to form, this provides a way to date the accretion of the Sun. To put the rapidity of the birth of the Solar System in human terms, this means pregnancy would last about twelve hours instead of nine months. It turns out that the birth of the Sun and Solar System was a relatively quick process after all.
In addition to researchers from the University of Münster and Lawrence Livermore National Laboratory, collaborators from the California Institute of Technology, Museum für Naturkunde in Berlin, and the University of California, Santa Cruz contributed to this work.
Gregory A. Brennecka, Christoph Burkhardt, Gerrit Budde, Thomas S. Kruijer, Francis Nimmo, Thorsten Kleine (2020). Astronomical context of Solar System formation from molybdenum isotopes in meteorite inclusions. Science. DOI: 0.1126/science.aaz8482