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According to a study published in the Astrophysical Journal, a team from the Max Planck Institute for Solar System Research (MPS) in Germany, comprising Nerea Gurrutxaga, Joanna Drazkowska, Vignesh Vaikundaraman, and Thorsten Kleine, this region produced planetesimals with several different compositions over a span of roughly two million years.

These planetesimals range from a few to hundreds of kilometres across. In the early years of our solar system, some planetesimals coalesced under gravity to form protoplanets and subsequently the Earth and other planets.

The baby sun was surrounded by a huge disk of dust and gas about 4.6 billion years ago. Some of this dust stuck together to form the planetesimals.

The process was far from simple. Studies across decades have shown that different segments of our solar system developed under different conditions, and that it took many stages of planet formation at the same time for it to be the way it is today.

The study primarily focused on a specific period of between two and four million years after the formation of the solar system. This was around the time when Jupiter’s gravity had mopped up the material close to its orbit.

While earlier studies had suggested that these dust traps were responsible for the quicker formation of planetesimals in the solar system, the recent computerised simulations suggested that these dust traps could very well continue to produce different types of bodies over a long period of time.

“Different types of planetesimals apparently formed in the same region of the early dust and gas disk, only at different times. The region just outside Jupiter’s orbit offered excellent conditions for this,” said Joanna Drążkowska.

The findings also showed a connection of these objects to the known groups of meteorites we can see on Earth.

“For the first time, we have succeeded in accurately reproducing the results of laboratory studies of meteorites using computer simulations of the early Solar System. The meteorites serve, so to speak, as a touchstone for theories of planetary formation,” said Thorsten Kleine.

Meteorites are pieces of space rock that make it through Earth’s atmosphere and land on the surface. Most are thought to be remnants of ancient planetesimals, largely unchanged since the earliest days of the Solar System.

The researchers paid particular attention to carbonaceous chondrites, a carbon-rich type of meteorite. Lab studies suggest these formed beyond Jupiter during the same window of time the simulations were modelling.

Scientists sort carbonaceous chondrites into six groups based on age and composition. Some are fragile and made almost entirely of fine-grained material, while others are more robust and contain visible inclusions embedded within the finer matter.

In the simulations, these two components mapped onto two kinds of material thought to have existed in the early Solar System – one being fragile and dusty, and the other consisting of sturdier clumps that formed early in hotter regions before spreading across the disk.

“For our simulations, it was crucial to model the behavior and interaction of both materials on both small and large scales,” said Nerea Gurrutxaga, PhD student at the MPS and first author of the paper.

The team’s models tracked everything from microscopic particle collisions to large-scale movement across the enormous gas disk. Particles could break apart, clump together, drift toward the Sun, or get trapped in certain regions.

What emerged was striking. Jupiter, it turned out, acted as a much stronger barrier for larger and sturdier particles than it did for smaller dust grains. Meanwhile, the ongoing formation of new planetesimals was steadily eating into the available material.

Over millions of years, these two effects together caused the two types of material to accumulate in different proportions beyond Jupiter’s orbit. That shifting balance is what ultimately gave rise to clearly distinct generations of planetesimals.

In the first 500,000 years, the proportion of crumbly material fell before climbing again over the next million years. Eventually, two separate populations of planetesimals emerged – one dominated by fragile material, and another by more stable matter.

The researchers also believe that other meteorite types beyond carbonaceous chondrites may have formed within the same dust trap, possibly during even earlier stages of Solar System history.

“There is strong evidence that dust traps were the preferred birthplace of planetesimals in our Solar System,” said Drążkowska.