When the solar system first took up the task of building solid bodies - such as planets, moons, and protoplanets - it basically had a choice between two ingredients. There were heat-forged chondrules, which were millimeter-sized bits of rock; and there was matrix, a fine-grained, cold dust loaded with water ice and organic molecules.
And from the get-go, the solar system chose fire.
In a new, Yale-led study, researchers provide the first geochemical evidence that within the first million years after the solar system began to form, it was already preferentially sorting for chondrules over matrix. Prior research had only been able to document this sorting process in objects that formed 2 to 4 million years after the solar system's origin.
The study was published Sept. 18 in the journal Nature Astronomy.
"Our work shows that this assembly process was remarkably selective from the very beginning," said Damanveer Grewal, an assistant professor of Earth and planetary sciences in Yale's Faculty of Arts and Sciences, and first author of the study. "The earliest bodies in the outer solar system were built from 83% to 92% chondrules, with very little of the icy, volatile-rich dust that dominates later-forming objects."
