How Planetesimals Formed in the Early Solar System
New research published on May 26 at 12:00 in The Astrophysical Journal sheds light on how planetesimals—the building blocks of planets—first emerged. Around 4.6 billion years ago, a ring-shaped region of high gas pressure formed beyond Jupiter's orbit, creating a cosmic nursery for these objects. Researchers at Germany's Max Planck Institute for Solar System Research (MPS) ran computer simulations showing that within two million years, this region gave rise to space rocks with diverse compositions.
Study Period and Key Findings
The study focused on the period between two and four million years after the birth of the Solar System. During this time, Jupiter carved a gap in the gas-and-dust disk, which in turn triggered the formation of a high-pressure gas ring. The simulated objects matched real meteorite groups, particularly carbonaceous chondrites, which lab analyses confirm originated beyond Jupiter during that same window.
In the first 500,000 years, the amount of loose material trapped in the ring decreased, but it rebounded over the next million years. This cycle produced two distinct populations of planetesimals:
- One made of fragile, loosely bound material;
- Another composed of more stable compounds that formed in hotter regions closer to the star.
These findings open new avenues for understanding how the Solar System evolved and how its components came together.
The results could significantly shape future research in astronomy and planetary science by offering fresh insights into the processes that built our Solar System. Establishing clear links between simulated planetesimals and actual meteorites may also help scientists better understand the composition and development of other planetary systems across the universe.