A sample from an asteroid lands at LLNL

The Japanese Aerospace Exploration Agency launched Hayabusa2 to the asteroid 162173 Ryugu in December 2014. The Lawrence Livermore National Laboratory cosmochemists were on high alert in December 2020 when the sample-return capsule successfully landed back on Earth with pristine pieces of Ryugu.

A proposal was drafted to obtain a subsample of the asteroid. The material is now on-site. It formed shortly after the birth of the sun, as a fragment of a larger asteroid. In addition to determining the materials from which the solar system formed, samples from this asteroid can also provide insight into how the system evolved.

In previous generations of stars, swirling gas and dust formed the solar system. 'Stardust' is particulate material of nanometer to micrometer size that affects the formation of planets, like Ryugu.

The study of Ryugu stardust is essential to determining the origin of the materials, such as which types of stars contributed to Ryugu's parent body, and hence our solar system,” said Ziva Shulaker, principal investigator of the project a. Isotopic composition of stardust tells us about the stellar environments in which it formed.

Meteorites are traditionally processed by separating the particles from the rest of the sample, then dissolving the remainder. A non-destructive sample preparation technique will assist the team in preserving as much of the sample materials as possible.

The stardust will be located by micro-computed tomography imaging of the sample. In order to determine the isotopic composition of particles, individual particles will be removed and analyzed by a mass spectrometer.

The isotopic datasets will be used to constrain the physical conditions, density, temperature, and timescale of element creation in the parent stars. It is necessary to establish Ryugu's relationship with other bodies in the solar system in order to reconstruct the more recent history of our solar system.

According to Quinn Shollenberger, scientist in charge of relating Ryugu to Earth and other known samples in meteorite collections in order to understand solar system formation, we are comparing Ryugu pieces against those previously measured chemical and isotopic signatures of different bodies in the solar system.

In order to better understand how the Earth formed and evolved, we are trying to learn as much as possible. The unique pristine nature of Ryugu makes bulk-rock measurements of Ryugu useful for establishing genetic relationships to planetary bodies and refining the accretion history of terrestrial planets.

The Ryugu meteorite has close affinities to C1 chondrites, which represent the bulk solar system composition. In order to test whether Earth formed from material similar to Ryugu, the team will analyze the iron isotopic composition of bulk samples of Ryugu.

Also, bulk-sample titanium, chromium, and nickel isotopics will be collected to study Earth's accretion from a protoplanetary disk.

The team also includes Greg Brennecka, Jan Render, Lars Borg, Michael Savina, and Wei Jia Ong. As a result of the team's work, we have gained a comprehensive understanding of how the solar system - and the Earth - got started and how it has evolved.