著者

Eizo NAKAMURA Katsura KOBAYASHI Ryoji TANAKA Tak KUNIHIRO Hiroshi KITAGAWA Christian POTISZIL Tsutomu OTA Chie SAKAGUCHI Masahiro YAMANAKA Dilan M. RATNAYAKE Havishk TRIPATHI Rahul KUMAR Maya-Liliana AVRAMESCU Hidehisa TSUCHIDA Yusuke YACHI Hitoshi MIURA Masanao ABE Ryota FUKAI Shizuho FURUYA Kentaro HATAKEDA Tasuku HAYASHI Yuya HITOMI Kazuya KUMAGAI Akiko MIYAZAKI Aiko NAKATO Masahiro NISHIMURA Tatsuaki OKADA Hiromichi SOEJIMA Seiji SUGITA Ayako SUZUKI Tomohiro USUI Toru YADA Daiki YAMAMOTO Kasumi YOGATA Miwa YOSHITAKE Masahiko ARAKAWA Atsushi FUJII Masahiko HAYAKAWA Naoyuki HIRATA Naru HIRATA Rie HONDA Chikatoshi HONDA Satoshi HOSODA Yu-ichi IIJIMA Hitoshi IKEDA Masateru ISHIGURO Yoshiaki ISHIHARA Takahiro IWATA Kosuke KAWAHARA Shota KIKUCHI Kohei KITAZATO Koji MATSUMOTO Moe MATSUOKA Tatsuhiro MICHIKAMI Yuya MIMASU Akira MIURA Tomokatsu MOROTA Satoru NAKAZAWA Noriyuki NAMIKI Hirotomo NODA Rina NOGUCHI Naoko OGAWA Kazunori OGAWA Chisato OKAMOTO Go ONO Masanobu OZAKI Takanao SAIKI Naoya SAKATANI Hirotaka SAWADA Hiroki SENSHU Yuri SHIMAKI Kei SHIRAI Yuto TAKEI Hiroshi TAKEUCHI Satoshi TANAKA Eri TATSUMI Fuyuto TERUI Ryudo TSUKIZAKI Koji WADA Manabu YAMADA Tetsuya YAMADA Yukio YAMAMOTO Hajime YANO Yasuhiro YOKOTA Keisuke YOSHIHARA Makoto YOSHIKAWA Kent YOSHIKAWA Masaki FUJIMOTO Sei-ichiro WATANABE Yuichi TSUDA

出版者

The Japan Academy

雑誌

Proceedings of the Japan Academy, Series B (ISSN:03862208)

巻号頁・発行日

vol.98, no.6, pp.227-282, 2022-06-10 (Released:2022-06-10)

参考文献数

245

被引用文献数

90

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Presented here are the observations and interpretations from a comprehensive analysis of 16 representative particles returned from the C-type asteroid Ryugu by the Hayabusa2 mission. On average Ryugu particles consist of 50% phyllosilicate matrix, 41% porosity and 9% minor phases, including organic matter. The abundances of 70 elements from the particles are in close agreement with those of CI chondrites. Bulk Ryugu particles show higher δ18O, Δ17O, and ε54Cr values than CI chondrites. As such, Ryugu sampled the most primitive and least-thermally processed protosolar nebula reservoirs. Such a finding is consistent with multi-scale H-C-N isotopic compositions that are compatible with an origin for Ryugu organic matter within both the protosolar nebula and the interstellar medium. The analytical data obtained here, suggests that complex soluble organic matter formed during aqueous alteration on the Ryugu progenitor planetesimal (several 10’s of km), <2.6 Myr after CAI formation. Subsequently, the Ryugu progenitor planetesimal was fragmented and evolved into the current asteroid Ryugu through sublimation.

著者

Aiko Nakato Shiori Inada Shizuho Furuya Masahiro Nishimura Toru Yada Masanao Abe Tomohiro Usui Hideto Yoshida Takashi Mikouchi Kanako Sakamoto Hajime Yano Yayoi N. Miura Yoshinori Takano Shinji Yamanouchi Ryuji Okazaki Hirotaka Sawada Shogo Tachibana

出版者

GEOCHEMICAL SOCIETY OF JAPAN

雑誌

GEOCHEMICAL JOURNAL (ISSN:00167002)

巻号頁・発行日

pp.GJ22017, (Released:2022-10-21)

被引用文献数

13

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The Hayabusa2 spacecraft explored C-type near-Earth asteroid (162173) Ryugu and returned asteroidal materials, collected during two touchdown operations, to the Earth as the first sample from carbonaceous-type asteroid. The sample container, in which ~5 g of Ryugu sample was enclosed, was safely opened in the clean chamber system with no severe exposure to the terrestrial atmosphere. In the course of preparation operation of the sample container, two dark-colored millimeter- to sub-millimeter-sized particles were found outside the sealing part of the sample container. Because they look similar to the Ryugu particles inside the sample container, the particles were named as Q particles (Q from questionable). In this study, we investigated Q particles (Q001 and Q002) mineralogically and petrographically to compare them with potential contaminants (the ablator material of the reentry capsule and fine sand particles at the capsule landing site), Ryugu sample, and CI chondrites. The Q particles show close resemblance to Ryugu sample and CI chondrites, but have no evidence of terrestrial weathering that CI chondrites experienced. We therefore conclude that the Q particles are originated from Ryugu and were expelled from the sample catcher (sample storage canister) in space prior to the enclosure operation of the sample catcher in the sample container. The most likely scenario is that the Q particles escaped from the sample catcher during the retrieval of the sample collection reflector, which was the necessary operation for the sample container closing.

著者

Sho SASAKI Masaki FUJIMOTO Hajime YANO Takeshi TAKASHIMA Yasumasa KASABA Yukihiro TAKAHASHI Jun KIMURA Yuichi TSUDA Ryu FUNASE Osamu MORI Stefano CAMPAGNOLA Yasuhiro KAWAKATSU

出版者

THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES

雑誌

TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, AEROSPACE TECHNOLOGY JAPAN (ISSN:18840485)

巻号頁・発行日

vol.10, no.ists28, pp.Tk_37-Tk_40, 2012 (Released:2013-06-07)

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EJSM (Europa Jupiter System Mission) is an international Jovian system mission with three spacecraft. Coordinated observation of Jovian magnetosphere is one of the important targets of the mission in addition to icy satellites, atmosphere, and the interior of Jupiter. JAXA will take a role on the magnetosphere spinner JMO (Jupiter Magnetospheric Orbiter), whereas ESA will launch JGO (Jupiter Ganymede Orbiter) and NASA will be responsible for JEO (Jupiter Europa Orbiter). One possibility is to combine JMO with a proposed solar sail mission of JAXA for Jupiter and one of Trojan asteroids. Since Trojan asteroids could be representing raw solid materials of Jupiter or at least outer solar system bodies,involvement of Trojan observation should enlarge the scope and enhance the quality of EJSM.

著者

Aiko Nakato Shiori Inada Shizuho Furuya Masahiro Nishimura Toru Yada Masanao Abe Tomohiro Usui Hideto Yoshida Takashi Mikouchi Kanako Sakamoto Hajime Yano Yayoi N. Miura Yoshinori Takano Shinji Yamanouchi Ryuji Okazaki Hirotaka Sawada Shogo Tachibana

出版者

GEOCHEMICAL SOCIETY OF JAPAN

雑誌

GEOCHEMICAL JOURNAL (ISSN:00167002)

巻号頁・発行日

vol.56, no.6, pp.197-222, 2022 (Released:2022-12-16)

参考文献数

60

被引用文献数

13

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The Hayabusa2 spacecraft explored C-type near-Earth asteroid (162173) Ryugu and returned asteroidal materials, collected during two touchdown operations, to the Earth as the first sample from carbonaceous-type asteroid. The sample container, in which ~5 g of Ryugu sample was enclosed, was safely opened in the clean chamber system with no severe exposure to the terrestrial atmosphere. In the course of preparation operation of the sample container, two dark-colored millimeter- to sub-millimeter-sized particles were found outside the sealing part of the sample container. Because they look similar to the Ryugu particles inside the sample container, the particles were named as Q particles (Q from questionable). In this study, we investigated Q particles (Q001 and Q002) mineralogically and petrographically to compare them with potential contaminants (the ablator material of the reentry capsule and fine sand particles at the capsule landing site), Ryugu sample, and CI chondrites. The Q particles show close resemblance to Ryugu sample and CI chondrites, but have no evidence of terrestrial weathering that CI chondrites experienced. We therefore conclude that the Q particles are originated from Ryugu and were expelled from the sample catcher (sample storage canister) in space prior to the enclosure operation of the sample catcher in the sample container. The most likely scenario is that the Q particles escaped from the sample catcher during the retrieval of the sample collection reflector, which was the necessary operation for the sample container closing.

著者

Akihiko Yamagishi Shin-ichi Yokobori Yoshitaka Yoshimura Masamichi Yamashita Hirofumi Hashimoto Takashi Kubota Hajime Yano Junichi Haruyama Makoto Tabata Kensei Kobayashi Hajime Honda Yuichi Utsumi Tsunemasa Saiki Takashi Itoh Atsuo Miyakawa Kenji Hamase Takeshi Naganuma Hajime Mita Kenichi Tonokura Sho Sasaki Hideaki Miyamoto

出版者

日本宇宙生物科学会

雑誌

Biological Sciences in Space (ISSN:09149201)

巻号頁・発行日

vol.24, no.2, pp.67-82, 2010 (Released:2012-06-26)

参考文献数

114

被引用文献数

1 12

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Liquid water is considered to be critical for life. Gibbs free energy is another factor that is important to sustain life for long durations. Gibbs free energy is obtained by reactions between reductants and oxidants, or from any other non-equilibrium state of matter. As an example, aerobic organisms use carbohydrates and oxygen to obtain energy. Many types of chemoautotrophic mechanisms are known for this process as well. On the surface of Mars, methane and oxidative compounds such as ferric oxide, sulfate and perchloride, which could provide redox-derived Gibbs free energy, have been detected. Iron-dependent methane oxidizing bacteria have been found in marine environments on Earth. This finding suggests the possible presence of methane-oxidizing bacteria on the Mars surface, if the local thermal environment and other resources permit proliferation and metabolism of bacteria. Our project aims to search for methane-oxidizing microbes on the Mars surface. Martian soil will be sampled from a depth of about 5 - 10 cm below the surface, where organisms are expected to be protected from the harsh hyper-oxidative environment of the Mars surface. Small particles less than 0.1 mm or 1 mm will be sieved from the sample, before being transferred to the analysis section by a micro-actuator. The particles will be stained with a cocktail of fluorescent reagents, and examined by fluorescence microscopy. A combination of fluorescent dyes has been selected to identify life forms in samples. A membrane-specific dye or a combination of dyes will be used to detect membranes surrounding the "cell". An intercalating fluorescent dye such as SYBR Green will be used to detect genetic compounds such as DNA. A substrate dye that emits fluorescence upon cleavage by a catalytic reaction will be used to detect the catalytic activity of the "cell". A combination of staining reagents has been chosen based on the definition of life. A membrane separating a cell from the ambient environment may lead to identification of an "individual". DNA or genetic material is required for "replication" of the life form. Catalytic reactions carried out by enzymes drive "metabolism". This combination of strategies will also be useful for detecting pre-biotic organic material as well as remnants of ancient life. Hydrolysis of the polymers in the "cell" followed by HPLC or soft ionization MS for amino acid analysis will be effective for examining whether Martian life is identical to or different from terrestrial life. The number and type of the amino acids as well as their chirality will be analyzed to distinguish whether the polymers are contaminants from Earth.