Joint Press Release
Shogo Tachibana (Professor, UTOPS, Department of Earth and Planetary Science, ISAS)

An international research group led by Senior Scientist Yoshinori Takano of the Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Professor Hiroshi Naraoka of Kyushu University, and Principal Investigator Jason Dworkin of the National Aeronautics and Space Administration (NASA), along with researchers from Keio University, Human Metabolome Technologies, Hokkaido University, Tohoku University, Hiroshima University, Nagoya University, Kyoto University, the University of Tokyo, extracted soluble components in samples from the asteroid Ryugu and performed precise chemical analysis. A total of 84 diverse organic acids (including newly discovered monocarboxylic, dicarboxylic, tricarboxylic, and hydroxy acids) and nitrogen-containing compounds with a high affinity for water were identified, providing conclusive evidence for the current state of chemical evolution and water quality metamorphism (Figure). These include oxalic acid, citric acid, malic acid, pyruvic acid, pyruvic acid, lactic acid, mevalonic acid, and others, as well as a group of alkylurea molecules, an organic-inorganic complex, revealing the origin of chemical evolution dominated only by physical and chemical factors. We then summarized the light element composition (carbon, nitrogen, hydrogen, oxygen, and sulfur) and organic material science properties, including stable isotope composition, molecular composition, and content, of the organic matter at the two touchdown sampling sites.

These results provide primary information on the chemical evolution of the early solar system and are important for understanding the larger scientific inquiry into how non-living organic molecules led to the evolutionary processes that ultimately led to the emergence of life.

This research was supported by Grant-in-Aid for Scientific Research on Innovative Areas (Grant-in-Aid for International Cooperative Research Enhancement, Project No. 21KK0062), the Institute of Low Temperature Science, Hokkaido University Joint Project, and other research grants.

The results were published in the scientific journal Nature Communications on July 10, 2024 (18:00 JST).

Asteroid Ryugu was once a parent body rich in water (H₂O) and has been repeatedly frozen/thawed during its evolution in the solar system. By analyzing soluble components with high precision, we found conclusive evidence of “aqueous alteration” recorded in hydrophilic organic molecules. A total of 84 new species (including structural isomers) of organic acids (65 newly identified species including oxalic acid, malonic acid, citric acid, malic acid, pyruvic acid, lactic acid, and mevalonic acid) and nitrogen-containing molecules (19 new organic-inorganic complexes including alkylureas) with high affinity to water were discovered. It is believed that the primary molecular evolution involving water-organic-mineral interactions is still underway.

For more information, please refer to the following

Graduate School of Science web: https://www.s.u-tokyo.ac.jp/en/press/10423/

Publication URL: https://www.nature.com/articles/s41467-024-49237-6

Professor Nicolas Dauphas, Department of the Geophysical Sciences, University of Chicago, visited UTOPS and gave a lecture “The origin and evolution of the Moon” from a cosmochemical perspective.

(2024.6.26)

esse-sense Academic Talk (The Yaesu Lighthouse Discussion Group) is a forum for businesspeople, community leaders, and others to think about the future together while gaining insight into the knowledge and perspectives of researchers. At the 5th meeting (held on May 21, 2024), Professor Tachibana introduced what was learned from the analysis of samples from the asteroid “Ryugu” brought back by the space probe “Hayabusa2” and the origin and evolution of the solar system as told by “rocks”.

During the lecture, Professor Tachibana explained with a replica of the container in which the Ryugu samples were brought back to Earth, showed videos and photos of real research sites, and talked about the latest research results. He talked with a twinkle in his eye, and the participants were increasingly listened to him with great interest.

After the lecture was over, the audience and online participants asked questions one after another, and Professor Tachibana answered each question closely. We were very glad that some elementary school students questioned and some people asked again and again. 30 minutes have passed in an instant, the Q&A session filled with the enthusiasm of everyone, including Professor Tachibana.

We want to broaden researches and educations of earth and planetary science through such discussion and to inform people about the fund to support the researches and educations of earth and planetary science.

“esse-sense Academic Talk (Yaesu Lighthouse Discussion)” was held in collaboration with Essence Inc. and the University of Tokyo URA.

　　Cooperated by NPO Miratuku

　　Co-organized by Mitsui Fudosan POTLUCK YAESU

Dr. Guy Libourel, Observatoire de la Côte d’Azur, Nice, visited UTOPS and gave a lecture “From Asteroid to Earth: The first results of the NASA OSIRIS-REx mission”.

He talked about the latest results on the mineralogy and petrology of samples retrieved from the asteroid Bennu.

(2024.4.30)

Joint Press Release
Shogo Tachibana (Professor, UTOPS, Department of Earth and Planetary Science, ISAS)

A research group led by Professor Yuki Kimura, Hokkaido University, Chief Researcher Takeharu Kato, Senior Staff, Satoshi Anada, Senior Engineer Ryuji Yoshida, and Chief Researcher Kazuo Yamamoto of the Fine Ceramics Center, Senior Staff Toshiaki Tanigaki of the Research and Development Group, Hitachi, Ltd, Associate Professor Kosuke Kurosawa of Kobe University, Professor Tomoki Nakamura of Tohoku University, Assistant Professor Masahiko Sato (currently Associate Professor at Tokyo University of Science) and Professor Shogo Tachibana of the School of Science at the University of Tokyo, Professor Takaaki Noguchi and Assistant Professor Toru Matsumoto of Kyoto University have examined the surface of samples (grains of sand) recovered from the asteroid Ryugu by the explorer Hayabusa2 using electron holography, a technique using an electron microscope that can visualize magnetic flux on a nano scale. As a result, they discovered a new microstructure consisting of framboidal pseudo-magnetite, which formed from magnetite (Fe₃O₄) particles through losing their magnetic properties by reduction, and numerous iron nanoparticles with a vortex magnetic domain structure scattered around pseudo-magnetite. Magnetic minerals are natural magnetic recording medium that can record environmental information of the early solar system. Previously known recording medium were almost exclusively magnetite and pyrrhotite which form during aqueous alteration in asteroids. The new microstructures discovered in this study, especially the large number of iron nanoparticles, may record information on the magnetic field in the early solar system after the aqueous alteration, which was not known before. Therefore, it is expected to be used as a new magnetic recording medium that can provide information on the formation history of the solar system, which has not yet been explored, thereby opening up a new science on the formation of the solar system.

The research results were published in Nature Communications on Monday, April 29, 2024 (JST).

For more information, please refer to the following

Graduate School of Science web: https://www.s.u-tokyo.ac.jp/en/press/10332/

Publication URL: https://www.nature.com/articles/s41467-024-47798-0

Professor Masahiro Hoshino (Department of Earth and Planetary Science), the first director of the UTokyo Organization for Planetary Space Science (UTOPS), gave his final lecture, “From Earth to Space, the World of Plasma,” on Monday, February 19, 2024, and the lecture was archived on YouTube.

Please watch it from the following link.

The EQUULEUS, an ultra-small spacecraft, has been selected for the Selection Committee’s Special Prize at the 6th Space Exploitation Prize organized by the Japanese Cabinet Office under the title of “Demonstration of Orbit Control Technology in the Earth-Moon Sphere Using an Ultra-small Spacecraft”.

Professor Ryu Funase of UTOPS is involved in the development of the EQUULEUS spacecraft.

Please refer to the following URL for details.

https://www8.cao.go.jp/space/prize/prize.html

On February 23, 2024, Professor Shogo Tachibana gave a lecture titled “Bringing Back Samples from Small Objects – Ryugu, Bennu, and Beyond” at Hibiki Hall, Taketoyo Community Arts Center Yumetaro Plaza.

Please refer to the following URL for details.