New work by scientists reveals previously unknown details about the oldest planetary objects in our solar system, which decayed as a result of long-standing collisions and eventually formed iron-rich meteorites. The results of the study, published in the journal Nature Geoscience, show that the various chemical signatures of these meteorites can be explained by the process of crystallization of the core in their parent bodies, deepening our understanding of the geochemistry that occurs during the youth of the solar system.
Many of the meteorites that swept through our planet’s atmosphere and crashed onto its surface were once part of larger objects that disintegrated at some point in the history of our solar system. The similarity of their chemical composition proves that they arose as part of the common parental bodies, even if they arrived here centuries apart from each other and in completely different places.
Deciphering the geological processes that formed these parent bodies could tell us more about the history of our solar system and the formation of the Earth. In order to truly understand what makes our planet capable of supporting life, and to look for habitable worlds elsewhere, it is very important to understand its inner space – past and present.
It was believed that iron meteorites are the remnants of the cores of their ancient, broken into parts of their parent bodies. The history of how their layers differed is recorded in their chemical composition, if readable.
There are four stable isotopes of iron. Each element contains a unique number of protons, but its isotopes have a different number of neutrons. This means that each isotope of iron has a slightly different mass than the others. As a result, some isotopes are preferable for some chemical reactions, which, in turn, affects the proportion of this isotope in the final reaction products.
Traces of this favoritism can be found in rock samples and can help figure out the processes that forged the parent bodies of the meteorite.
Previous studies on the ratio of iron isotopes in iron meteorites have led to an astonishing observation: compared to the raw materials from which their mother bodies were created, they are enriched in heavy iron isotopes.
Scientists have determined that this enrichment can be fully explained by the crystallization of the parent object’s core.
The researchers used laboratory mimicry to model core crystallization temperatures in the parent bodies of iron meteorites: complex models of the crystallization process, including other concentrations of elements such as gold and iridium, as well as iron isotopes.
This improved understanding of core crystallization expands scientists’ knowledge of the formation period of our solar system, the scientists conclude.