JAMSTEC, Kyushu University, AIST, Hokkaido University, Thermo Fisher Scientific Japan Group,
HORIBA Advanced Techno, Co., Ltd., HORIBA TECHNO SERVICE CO., LTD.,
Tokyo Institute of Technology, School of Science, The University of Tokyo

Summary of Presentations

Japan Agency for Marine-Earth Science and Technology (Executive Vice President: Hiroyuki Yamato, hereinafter referred to as "JAMSTEC") The international collaborative research group led by Dr. Toshihiro Yoshimura, Senior Staff, and Dr. Yoshisaki Takano, Senior Staff, at the Center for Biogeochemistry, Marine Functional Application Division, National Institute of Advanced Industrial Science and Technology (AIST), National University Corporation, Professor Hiroshi Naraoka at the Graduate School of Science, Kyushu University, and others, has joined forces with the National Institute of Advanced Industrial Science and Technology (AIST), Horiba Advanced Techno, Inc. The group, together with researchers from the School of Science, the University of Tokyo, National Institute of Advanced Industrial Science and Technology, Horiba Techno, Horiba Techno Service, Thermo Fisher Scientific Japan Group, Hokkaido University, and Tokyo Institute of Technology, conducted precise chemical analysis of soluble components in samples from the asteroid Ryuguu to determine their composition, content, etc. The results of the analysis are shown in Table 1. The composition and content of the soluble components were clarified.

Asteroid Ryuguu is one of the primordial bodies that retain the chemical composition of the entire solar system before the birth of the Earth. The initial analysis of Hayabusa2 has revealed various properties, contents, and history of the asteroid, but the material information of ionic components among soluble components has remained unknown.

In this study, we extracted soluble components from samples of the asteroid Ryuguu and performed precise chemical analysis at the inorganic and organic molecular levels. The results showed that hydrothermal extracts, which reflect the most soluble components, are very rich in sodium ions ( ^Na+). Sodium ions act as electrolytes that stabilize the surface charge of minerals and organic matter, and some are thought to precipitate as sodium salts (Salt) by binding with organic molecules and other substances. Various organosulfur molecules were also found in the extract. It is thought that the chemical state of the organic sulfur molecules in the water on the asteroid Ryuguu has been changed by dissolution, and that they have chemically evolved into a wide variety of organosulfur molecules.

This finding is important not only for unraveling the material evolution of the early solar system, but also for answering the major question of how they led to the chemical processes that ultimately led to the birth of life.

The results will be published in the scientific journal Nature Communications on September 18, 2023 (Japan Standard Time).

Asteroid Explorer "Hayabusa2" returning samples containing salt and new sulfur molecules from the asteroid Ryuguu (©JAMSTEC)

The water (H2O) contained on the asteroid Ryuguu is thought to have been repeatedly frozen/thawed during its evolution in the solar system, dissolving and precipitating salts and other substances contained in minerals. By analyzing the soluble components, we can unravel the formation of the first "salt".

For more information, please visit the JAMSTEC website.

Published Journals

Journal name	Nature Communications
Title of paper	Chemical evolution of primordial salts and organic sulfur molecules in the asteroid 162173 Ryugu
DOI	s41467-023-40871-0