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.

On February 20, 2024 (Tue.), a book by Professor Shogo Tachibana of the UTOPS, titled “What did Hayabusa2 bring back?” was published.

Please refer to the following URL for details.

https://www.iwanami.co.jp/book/b639909.html

UTokyo Organization for Planetary Space Science (UTOPS) cooperated with the “Special Exhibition of Asteroid Itokawa and Ryugu Samples in Akashi” held from January 27 (Sat) to February 18 (Sun), 2024, at the 3rd floor exhibition room “Astronomy Gallery” of Akashi Municipal Planetarium.

Samples from the asteroid Itokawa, brought back to Earth by the asteroid explorer Hayabusa in June 2010, and samples from the asteroid Ryugu, brought back to Earth by the asteroid explorer Hayabusa2 in December 2020, were displayed side by side.

In conjunction with the exhibition, Professor Shogo Tachibana gave a lecture entitled “What the Stones of Asteroid Ryugu Have Begun to Tell Us” on January 28, 2024, at the planetarium dome on the second floor of the museum.

For details, please refer to the following URL.

We co-organized the Solar System symposium in Sapporo 2024 from February 13 (Tue.) to 15 (Thu.), 2024, at the Rusutsu Resort in Hokkaido, Japan.

About 40 participants from Japan and overseas discussed the formation and early evolution of the solar system.

On the second day, February 14 (Wednesday), we invited Professor Harold C. Connolly Jr., OSIRIS-REx Mission Sample Scientist, to give a lecture on the return samples from the asteroid Bennu.

Please refer to the following URL for details.

https://3s2024.webnode.jp