Almost 6% of the Earth’s mass comes from elements contributed by asteroids that arrived from the outer Solar System, in the initial moments of its formation. Analysis of samples from the Ryugu asteroid, provided by the Japanese Hayabusa2 mission, indicates that the isotopic composition of zinc and copper present in this space rock corresponds to conditions on Earth.
A new study recently published in the journal Nature Astronomy shows compelling evidence of the contribution of asteroids from the outer Solar System to the mass of the Earth, during the process of formation of our planet. The researchers concluded that between 5% and 6% of the Earth’s mass it was formed thanks to the contribution of these space rocks, which delivered zinc, copper and other volatile elements.
almost a part of the sun
Scientists from the Institute of Physics of the Globe in Paris, the University of Paris Cité and the National Center for Scientific Research (CNRS), in France, carried out a new analysis on samples from the asteroid Ryugu, which the Japanese Hayabusa2 mission brought to Earth in 2020. In the new work, they revealed the isotopic composition of zinc and copper in this body, considered a pristine and unaltered example of the type of meteorites that hit Earth in the early Solar System.
The analyzes carried out, carried out with the collaboration of an international team of specialists, show that the composition of the asteroid Ryugu is similar to that observed in carbonaceous chondrites, meteorites that are chemically most primitive and have the closest composition to the Sun. Many of these bodies, such as the Ivuna meteorite, are examples of meteorites from the outer Solar System that struck the early Earth.
Isotopic signatures show that the composition of Ryugu and Ivuna-like carbonaceous chondrites represent a significant part of the Earth’s mass. Specifically, zinc and copper are two moderately volatile elements that are key to studying the accretion processes of this type of material during the formation of terrestrial planets like ours.
strong similarities
The different groups of carbonaceous chondrites show different isotopic compositions of zinc and copper, but in this case it has been possible to verify a correspondence between Ryugu and the materials contributed by meteorites from the Solar System outside the Earth. According to one Press releasethe isotopic ratios of copper and zinc in the Ryugu samples were identical to those presented by carbonaceous chondrites that impacted on Earthbut different from all other types of meteorites.
By finally confirming the similarity between Ryugu and carbonaceous chondrites, the new study establishes that the samples obtained by the Japanese mission represent the best estimate available to date of the solar composition, specifically around copper and zinc. In addition, they provide a new vision of the important contribution of this type of body to the mass of the Earth, specifically in terms of the proportion of volatile elements.
Reference
Contribution of Ryugu-like material to Earth’s volatile inventory by Cu and Zn isotopic analysis. Marine Paquet, Frederic Moynier, Tetsuya Yokoyama et al. Nature Astronomy (2022). DOI:https://doi.org/10.1038/s41550-022-01846-1