Ryugu samples reveal Earth’s climate

A groundbreaking study conducted by an international team of scientists has revealed unprecedented insight into the nature of asteroid Ryugu, revealing the composition of the solar system’s water- and carbon-rich small body.

Asteroids like Ryugu are the embryonic remains of planets that never reached large size, providing a valuable window into the material that formed in the early solar system. The research centered on laboratory measurements of samples brought back to Earth by the Hayabusa2 spacecraft in 2020. Hayabusa2, led by the Japan Aerospace Exploration Agency (JAXA), aimed to uncover Ryugu’s true nature and explore how astrologers can use the knowledge gained from the meteorite. Interpreting telescopic observations of other hydrous asteroids.

Unlike meteorites from similar hydrous asteroids, the Ryugu samples avoided terrestrial changes that interact with oxygen and water in Earth’s atmosphere.

Reflection spectroscopy, a key technique linking laboratory analysis of meteorites and asteroid observations, was used to compare fresh Ryugu samples with meteorites altered in the Earth’s environment. The team was able to develop an analytical procedure that avoids exposing the samples to Earth’s atmosphere and ensures their original state is preserved.

Previous studies have suggested that the mineralogy of Ryugu samples is chemically similar to CI chondrites, the most primitive meteorites. However, other studies contradict this, revealing significant differences in the reflectance spectra of Ryugu samples and CI chondrites. Further investigation in the new study shows that heating the CI sample under reducing conditions at 300°C better reproduces the mineralogy of the Ryugu sample, resulting in a spectrum that closely matches that of the Ryugu sample. Ta.

This discovery challenges previous assumptions about the parent bodies of CI chondrites and highlights the susceptibility of the protometeorite spectrum to Earth’s weathering. This study suggests that the actual CI chondrite matrix likely exhibits a darker and flatter reflectance spectrum than previously thought.

“This study opens new avenues for understanding the composition and evolution of small bodies in the Solar System. By taking into account the effects of Earth weathering on meteorites, we can improve interpretations of asteroid composition and “We can advance knowledge about the history of the solar system,” said Kana Amano, a former doctoral student in Tohoku University’s Early Solar System Evolution Research Group and co-author of the paper.

Details of Amano et al.’s discovery were published in a magazine. scientific progress On December 6, 2023.

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