Yale: Solar System's First Bodies Were Built From Chondrules, Not Ice

A Yale-led study provides the first geochemical evidence that aerodynamic sorting of building material was already underway within the solar system's first million years. Using sulfur and iron oxidation state as tracers in iron meteorites, researchers reconstructed the composition of the earliest planetesimals: 83–92% chondrules and only 8–17% ice-rich matrix.

• Early planetesimals were 83–92% chondrules and just 8–17% matrix
• Matrix share is lower than in any known chondrite
• Sorting was established within the first million years
• Findings published September 18 in Nature Astronomy