Our solar system was formed in less than 200,000 years

The oldest solids framed in the Solar System are inclusions rich in calcium-aluminum (CAI), small metal droplets subsequently incorporated into meteorites. The ages of the CAI are considered to be the age of the Solar System, however to what exact moment in the arrangement of the stars they correspond has not been clear.

New research conducted by a group of scientists at Lawrence Livermore National Laboratory (LLNL), examining isotopes of the element molybdenum found on meteorites, suggests that our sun and solar system formed over the short period of 200,000 years.

Observing other star systems that formed similarly to ours, astronomers estimate that it presumably takes around 1-2 million years for a cloud to collapse and start a star. This is the first study to provide numbers on our solar system.

LLNL cosmochemist Greg Brennecka, lead author of a paper, said: “This work shows that this collapse, which led to the formation of the solar system, happened very quickly, in less than 200,000 years. If we scale all of this down to human lifespan, the formation of the solar system would be comparable to a pregnancy lasting about 12 hours instead of nine months. This was a quick process. “

The micrometer-to-centimeter inclusions of CAI in a high temperature environment (more than 1,300 Kelvin), probably near the young sun. They were then transported outward to the region where the carbonaceous chondrite meteorites (and their parent bodies) formed, where they are today. Most of the CAI was formed 4.567 billion years ago, in about 40,000-200,000 years.

In this study, scientists measured the isotopic and trace element compositions of molybdenum (Mo) of a variety of CAIs taken from carbonaceous chondrite meteorites, including Allende, the largest carbonaceous chondrite found on Earth. Because they found that the distinct Mo isotopic compositions of the CAIs cover the full range of material framed in the protoplanetary disk rather than just a small slice, these inclusions likely formed within the time frame of the cloud collapse.

Since the observed time span of stellar accretion (1-2 million years) is much longer than the CAIs formed, the team was able to pinpoint which astronomical phase the CAI formed in the formation of the solar system and ultimately how quickly the material that makes up the solar system accumulated.

Journal reference:

1. Gregory A. Brennecke et al. Astronomical context of the formation of the Solar System from molybdenum isotopes in meteorite inclusions, Science (2020). DOI: 10.1126 / science.aaz8482