The team identifies parent body materials in the Ryugu asteroid

The team identifies parent body materials in the Ryugu asteroid

A particle of the Ryugu asteroid (called C0009) helps identify the spacecraft’s parent body materials. Credit: A. Yamaguchi/NIPR

An international team including a researcher from the Lawrence Livermore National Laboratory (LLNL) has determined that a specific particle on the asteroid Ryugu can shed light on the unaltered primordial materials of its parent body.

In December 2014, the Japan Aerospace Exploration Agency launched the Hayabusa2 spacecraft to asteroid 162173 Ryugu. In December 2020, the sample-return capsule landed safely back on Earth with intact pieces of Ryugu that it had collected.

Ryugu is an ancient fragment of a larger asteroid that formed very early in the history of the solar system, shortly after the birth of the sun. Samples from this asteroid provide a unique opportunity to determine not only the material the solar system is made of, but also how the solar system evolved.

The Solar System is formed from a large cloud of swirling gas and dust made by previous generations of stars. This “stardust” is nanometer to micrometer sized particles that are incorporated into planetary bodies like Ryugu as they form.

In the new research, LLNL secondary ion mass spectrometer and cosmochemist Ming-Chang Liu (Nuclear and Chemical Sciences Division) found that one particle (called C0009) differs mineralogically from other Ryugu particles because it contains a small amount (~0.5 vol%) of anhydrous silicates. Other particles studied to date contained more phyllosilicate and carbonate minerals, suggesting that Ryugu underwent extensive aqueous alteration on its parent body, similar to the rare mineralogically altered but chemically primitive CI chondrites (a group of rare stony meteorites ). The research appears in Natural astronomy.

Through isotopic analysis of magnesium-rich olivine and pyroxene, the data “provide strong evidence that amoeboid olivine aggregates and magnesium-rich chondrules, two types of high-temperature objects formed in the solar nebula, accumulated in Ryugu’s parent body,” said Liu, who serves as the paper’s first author.

The team analyzed the results of oxygen isotope measurements of Ryugu’s anhydrous silicates, which have strong implications for the origin of Ryugu and, by extension, the parent asteroids of CI chondrite meteorites.

“Oxygen isotope data together with grain morphology allow us to infer the original materials incorporated in the protolith of Ryugu, as they reveal a potential relationship between anhydrous silicates in C0009 and other known high-temperature components found in non-CI carbonaceous chondrites, Liu said. .

Dust grains from the asteroid Ryugu older than our solar system

More information:
Ming-Chang Liu et al., Incorporation of 16O-rich anhydrous silicates in the protolith of highly hydrated asteroid Ryugu, Natural astronomy (2022). DOI: 10.1038/s41550-022-01762-4

Provided by Lawrence Livermore National Laboratory

Citation: Team identifies parent body materials in asteroid Ryugu (2022, September 23) Retrieved September 23, 2022, from

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