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1. Water circulation in Ryugu asteroid affected the distribution of nucleosynthetic isotope anomalies in returned sample.

Author

Yokoyama, Tetsuya, Wadhwa, Meenakshi, Iizuka, Tsuyoshi, Rai, Vinai, Gautam, Ikshu, Hibiya, Yuki, Masuda, Yuki, Haba, Makiko, Fukai, Ryota, Hines, Rebekah, Phelan, Nicole, Abe, Yoshinari, Aléon, Jérôme, Alexander, Conel, Amari, Sachiko, Amelin, Yuri, Bajo, Ken-Ichi, Bizzarro, Martin, Bouvier, Audrey, Carlson, Richard, Chaussidon, Marc, Choi, Byeon-Gak, Dauphas, Nicolas, Davis, Andrew, Di Rocco, Tommaso, Fujiya, Wataru, Hidaka, Hiroshi, Homma, Hisashi, Hoppe, Peter, Huss, Gary, Ichida, Kiyohiro, Ireland, Trevor, Ishikawa, Akira, Itoh, Shoichi, Kawasaki, Noriyuki, Kita, Noriko, Kitajima, Koki, Kleine, Thorsten, Komatani, Shintaro, Krot, Alexander, Liu, Ming-Chang, McKeegan, Kevin, Morita, Mayu, Motomura, Kazuko, Moynier, Frédéric, Nakai, Izumi, Nagashima, Kazuhide, Nguyen, Ann, Nittler, Larry, Onose, Morihiko, Pack, Andreas, Park, Changkun, Piani, Laurette, Qin, Liping, Russell, Sara, Sakamoto, Naoya, Schönbächler, Maria, Tafla, Lauren, Tang, Haolan, Terada, Kentaro, Terada, Yasuko, Usui, Tomohiro, Wada, Sohei, Walker, Richard, Yamashita, Katsuyuki, Yoneda, Shigekazu, Young, Edward, Yui, Hiroharu, Zhang, Ai-Cheng, Nakamura, Tomoki, Naraoka, Hiroshi, Noguchi, Takaaki, Okazaki, Ryuji, Sakamoto, Kanako, Yabuta, Hikaru, Abe, Masanao, Miyazaki, Akiko, Nakato, Aiko, Nishimura, Masahiro, Okada, Tatsuaki, Yada, Toru, Yogata, Kasumi, Nakazawa, Satoru, Saiki, Takanao, Tanaka, Satoshi, Terui, Fuyuto, Tsuda, Yuichi, Watanabe, Sei-Ichiro, Yoshikawa, Makoto, Tachibana, Shogo, Yurimoto, Hisayoshi, and Yin, Qing-Zhu

Abstract

Studies of material returned from Cb asteroid Ryugu have revealed considerable mineralogical and chemical heterogeneity, stemming primarily from brecciation and aqueous alteration. Isotopic anomalies could have also been affected by delivery of exogenous clasts and aqueous mobilization of soluble elements. Here, we show that isotopic anomalies for mildly soluble Cr are highly variable in Ryugu and CI chondrites, whereas those of Ti are relatively uniform. This variation in Cr isotope ratios is most likely due to physicochemical fractionation between 54Cr-rich presolar nanoparticles and Cr-bearing secondary minerals at the millimeter-scale in the bulk samples, likely due to extensive aqueous alteration in their parent bodies that occurred [Formula: see text] after Solar System birth. In contrast, Ti isotopes were marginally affected by this process. Our results show that isotopic heterogeneities in asteroids are not all nebular or accretionary in nature but can also reflect element redistribution by water.

Published
2023

2. Abundant presolar grains and primordial organics preserved in carbon-rich exogenous clasts in asteroid Ryugu.

Author

Nguyen, Ann, Mane, Prajkta, Keller, Lindsay, Piani, Laurette, Abe, Yoshinari, Aléon, Jérôme, Alexander, Conel, Amari, Sachiko, Amelin, Yuri, Bajo, Ken-Ichi, Bizzarro, Martin, Bouvier, Audrey, Carlson, Richard, Chaussidon, Marc, Choi, Byeon-Gak, Dauphas, Nicolas, Davis, Andrew, Di Rocco, Tommaso, Fujiya, Wataru, Fukai, Ryota, Gautam, Ikshu, Haba, Makiko, Hibiya, Yuki, Hidaka, Hiroshi, Homma, Hisashi, Hoppe, Peter, Huss, Gary, Ichida, Kiyohiro, Iizuka, Tsuyoshi, Ireland, Trevor, Ishikawa, Akira, Itoh, Shoichi, Kawasaki, Noriyuki, Kita, Noriko, Kitajima, Kouki, Kleine, Thorsten, Komatani, Shintaro, Krot, Alexander, Liu, Ming-Chang, Masuda, Yuki, McKeegan, Kevin, Morita, Mayu, Motomura, Kazuko, Moynier, Frédéric, Nakai, Izumi, Nagashima, Kazuhide, Nesvorný, David, Nittler, Larry, Onose, Morihiko, Pack, Andreas, Park, Changkun, Qin, Liping, Russell, Sara, Sakamoto, Naoya, Schönbächler, Maria, Tafla, Lauren, Tang, Haolan, Terada, Kentaro, Terada, Yasuko, Usui, Tomohiro, Wada, Sohei, Wadhwa, Meenakshi, Walker, Richard, Yamashita, Katsuyuki, Yokoyama, Tetsuya, Yoneda, Shigekazu, Young, Edward, Yui, Hiroharu, Zhang, Ai-Cheng, Nakamura, Tomoki, Naraoka, Hiroshi, Noguchi, Takaaki, Okazaki, Ryuji, Sakamoto, Kanako, Yabuta, Hikaru, Abe, Masanao, Miyazaki, Akiko, Nakato, Aiko, Nishimura, Masahiro, Okada, Tatsuaki, Yada, Toru, Yogata, Kasumi, Nakazawa, Satoru, Saiki, Takanao, Tanaka, Satoshi, Terui, Fuyuto, Tsuda, Yuichi, Watanabe, Sei-Ichiro, Yoshikawa, Makoto, Tachibana, Shogo, Yurimoto, Hisayoshi, and Yin, Qing-Zhu

Subjects
Carbon, Solar System, Meteoroids, Silicates
Abstract

Preliminary analyses of asteroid Ryugu samples show kinship to aqueously altered CI (Ivuna-type) chondrites, suggesting similar origins. We report identification of C-rich, particularly primitive clasts in Ryugu samples that contain preserved presolar silicate grains and exceptional abundances of presolar SiC and isotopically anomalous organic matter. The high presolar silicate abundance (104 ppm) indicates that the clast escaped extensive alteration. The 5 to 10 times higher abundances of presolar SiC (~235 ppm), N-rich organic matter, organics with N isotopic anomalies (1.2%), and organics with C isotopic anomalies (0.2%) in the primitive clasts compared to bulk Ryugu suggest that the clasts formed in a unique part of the protoplanetary disk enriched in presolar materials. These clasts likely represent previously unsampled outer solar system material that accreted onto Ryugu after aqueous alteration ceased, consistent with Ryugus rubble pile origin.

Published
2023

3. Presolar stardust in asteroid Ryugu

Author

Barosch, Jens, Nittler, Larry R., Wang, Jianhua, Alexander, Conel M. O'D., De Gregorio, Bradley T., Engrand, Cécile, Kebukawa, Yoko, Nagashima, Kazuhide, Stroud, Rhonda M., Yabuta, Hikaru, Abe, Yoshinari, Aléon, Jérôme, Amari, Sachiko, Amelin, Yuri, Bajo, Ken-ichi, Bejach, Laure, Bizzarro, Martin, Bonal, Lydie, Bouvier, Audrey, Carlson, Richard W., Chaussidon, Marc, Choi, Byeon-Gak, Cody, George D., Dartois, Emmanuel, Dauphas, Nicolas, Davis, Andrew M., Dazzi, Alexandre, Deniset-Besseau, Ariane, Di Rocco, Tommaso, Duprat, Jean, Fujiya, Wataru, Fukai, Ryota, Gautam, Ikshu, Haba, Makiko K., Hashiguchi, Minako, Hibiya, Yuki, Hidaka, Hiroshi, Homma, Hisashi, Hoppe, Peter, Huss, Gary R., Ichida, Kiyohiro, Iizuka, Tsuyoshi, Ireland, Trevor R., Ishikawa, Akira, Ito, Motoo, Itoh, Shoichi, Kamide, Kanami, Kawasaki, Noriyuki, Kilcoyne, A. L. David, Kita, Noriko T., Kitajima, Kouki, Kleine, Thorsten, Komatani, Shintaro, Komatsu, Mutsumi, Krot, Alexander N., Liu, Ming-Chang, Martins, Zita, Masuda, Yuki, Mathurin, Jérémie, McKeegan, Kevin D., Montagnac, Gilles, Morita, Mayu, Mostefaoui, Smail, Motomura, Kazuko, Moynier, Frédéric, Nakai, Izumi, Nguyen, Ann N., Ohigashi, Takuji, Okumura, Taiga, Onose, Morihiko, Pack, Andreas, Park, Changkun, Piani, Laurette, Qin, Liping, Quirico, Eric, Remusat, Laurent, Russell, Sara S., Sakamoto, Naoya, Sandford, Scott A., Schönbächler, Maria, Shigenaka, Miho, Suga, Hiroki, Tafla, Lauren, Takahashi, Yoshio, Takeichi, Yasuo, Tamenori, Yusuke, Tang, Haolan, Terada, Kentaro, Terada, Yasuko, Usui, Tomohiro, Verdier-Paoletti, Maximilien, Wada, Sohei, Wadhwa, Meenakshi, Wakabayashi, Daisuke, Walker, Richard J., Yamashita, Katsuyuki, Yamashita, Shohei, Yin, Qing-Zhu, Yokoyama, Tetsuya, Yoneda, Shigekazu, Young, Edward D., Yui, Hiroharu, Zhang, Ai-Cheng, Abe, Masanao, Miyazaki, Akiko, Nakato, Aiko, Nakazawa, Satoru, Nishimura, Masahiro, Okada, Tatsuaki, Saiki, Takanao, Tanaka, Satoshi, Terui, Fuyuto, Tsuda, Yuichi, Watanabe, Sei-ichiro, Yada, Toru, Yogata, Kasumi, Yoshikawa, Makoto, Nakamura, Tomoki, Naraoka, Hiroshi, Noguchi, Takaaki, Okazaki, Ryuji, Sakamoto, Kanako, Tachibana, Shogo, and Yurimoto, Hisayoshi

Subjects
Astrophysics - Earth and Planetary Astrophysics, Astrophysics - Solar and Stellar Astrophysics
Abstract

We have conducted a NanoSIMS-based search for presolar material in samples recently returned from C-type asteroid Ryugu as part of JAXA's Hayabusa2 mission. We report the detection of all major presolar grain types with O- and C-anomalous isotopic compositions typically identified in carbonaceous chondrite meteorites: 1 silicate, 1 oxide, 1 O-anomalous supernova grain of ambiguous phase, 38 SiC, and 16 carbonaceous grains. At least two of the carbonaceous grains are presolar graphites, whereas several grains with moderate C isotopic anomalies are probably organics. The presolar silicate was located in a clast with a less altered lithology than the typical extensively aqueously altered Ryugu matrix. The matrix-normalized presolar grain abundances in Ryugu are 4.8$^{+4.7}_{-2.6}$ ppm for O-anomalous grains, 25$^{+6}_{-5}$ ppm for SiC grains and 11$^{+5}_{-3}$ ppm for carbonaceous grains. Ryugu is isotopically and petrologically similar to carbonaceous Ivuna-type (CI) chondrites. To compare the in situ presolar grain abundances of Ryugu with CI chondrites, we also mapped Ivuna and Orgueil samples and found a total of SiC grains and 6 carbonaceous grains. No O-anomalous grains were detected. The matrix-normalized presolar grain abundances in the CI chondrites are similar to those in Ryugu: 23 $^{+7}_{-6}$ ppm SiC and 9.0$^{+5.3}_{-4.6}$ ppm carbonaceous grains. Thus, our results provide further evidence in support of the Ryugu-CI connection. They also reveal intriguing hints of small-scale heterogeneities in the Ryugu samples, such as locally distinct degrees of alteration that allowed the preservation of delicate presolar material., Comment: 12 pages, 3 figures, 2 tables. Published in ApJL

Published
2022
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4. Oxygen isotopes of anhydrous primary minerals show kinship between asteroid Ryugu and comet 81P/Wild2

Author

Kawasaki, Noriyuki, Nagashima, Kazuhide, Sakamoto, Naoya, Matsumoto, Toru, Bajo, Ken-ichi, Wada, Sohei, Igami, Yohei, Miyake, Akira, Noguchi, Takaaki, Yamamoto, Daiki, Russell, Sara S, Abe, Yoshinari, Aléon, Jérôme, Alexander, Conel M O’D, Amari, Sachiko, Amelin, Yuri, Bizzarro, Martin, Bouvier, Audrey, Carlson, Richard W, Chaussidon, Marc, Choi, Byeon-Gak, Dauphas, Nicolas, Davis, Andrew M, Di Rocco, Tommaso, Fujiya, Wataru, Fukai, Ryota, Gautam, Ikshu, Haba, Makiko K, Hibiya, Yuki, Hidaka, Hiroshi, Homma, Hisashi, Hoppe, Peter, Huss, Gary R, Ichida, Kiyohiro, Iizuka, Tsuyoshi, Ireland, Trevor R, Ishikawa, Akira, Ito, Motoo, Itoh, Shoichi, Kita, Noriko T, Kitajima, Kouki, Kleine, Thorsten, Komatani, Shintaro, Krot, Alexander N, Liu, Ming-Chang, Masuda, Yuki, McKeegan, Kevin D, Morita, Mayu, Motomura, Kazuko, Moynier, Frédéric, Nakai, Izumi, Nguyen, Ann, Nittler, Larry, Onose, Morihiko, Pack, Andreas, Park, Changkun, Piani, Laurette, Qin, Liping, Schönbächler, Maria, Tafla, Lauren, Tang, Haolan, Terada, Kentaro, Terada, Yasuko, Usui, Tomohiro, Wadhwa, Meenakshi, Walker, Richard J, Yamashita, Katsuyuki, Yin, Qing-Zhu, Yokoyama, Tetsuya, Yoneda, Shigekazu, Young, Edward D, Yui, Hiroharu, Zhang, Ai-Cheng, Nakamura, Tomoki, Naraoka, Hiroshi, Okazaki, Ryuji, Sakamoto, Kanako, Yabuta, Hikaru, Abe, Masanao, Miyazaki, Akiko, Nakato, Aiko, Nishimura, Masahiro, Okada, Tatsuaki, Yada, Toru, Yogata, Kasumi, Nakazawa, Satoru, Saiki, Takanao, Tanaka, Satoshi, Terui, Fuyuto, Tsuda, Yuichi, Watanabe, Sei-ichiro, Yoshikawa, Makoto, Tachibana, Shogo, and Yurimoto, Hisayoshi

Subjects
Earth Sciences, Physical Sciences, Space Sciences, Geology, Prevention
Abstract

The extraterrestrial materials returned from asteroid (162173) Ryugu consist predominantly of low-temperature aqueously formed secondary minerals and are chemically and mineralogically similar to CI (Ivuna-type) carbonaceous chondrites. Here, we show that high-temperature anhydrous primary minerals in Ryugu and CI chondrites exhibit a bimodal distribution of oxygen isotopic compositions: 16O-rich (associated with refractory inclusions) and 16O-poor (associated with chondrules). Both the 16O-rich and 16O-poor minerals probably formed in the inner solar protoplanetary disk and were subsequently transported outward. The abundance ratios of the 16O-rich to 16O-poor minerals in Ryugu and CI chondrites are higher than in other carbonaceous chondrite groups but are similar to that of comet 81P/Wild2, suggesting that Ryugu and CI chondrites accreted in the outer Solar System closer to the accretion region of comets.

Published
2022

6. Pyrrhotites in asteroid 162173 Ryugu: Records of the initial changes on their surfaces with aqueous alteration

Author

Yui, Hiroharu, Urashima, Shu-hei, Onose, Morihiko, Morita, Mayu, Komatani, Shintaro, Nakai, Izumi, Abe, Yoshinari, Terada, Yasuko, Homma, Hisashi, Motomura, Kazuko, Ichida, Kiyohiro, Yokoyama, Tetsuya, Nagashima, Kazuhide, Aléon, Jérôme, M. O’D. Alexander, Conel, Amari, Sachiko, Amelin, Yuri, Bajo, Ken-ichi, Bizzarro, Martin, Bouvier, Audrey, Carlson, Richard W., Chaussidon, Marc, Choi, Byeon-Gak, Dauphas, Nicolas, Davis, Andrew M., Fujiya, Wataru, Fukai, Ryota, Gautam, Ikshu, Haba, Makiko K., Hibiya, Yuki, Hidaka, Hiroshi, Hoppe, Peter, Huss, Gary R., Iizuka, Tsuyoshi, Ireland, Trevor R., Ishikawa, Akira, Itoh, Shoichi, Kawasaki, Noriyuki, Kita, Noriko T., Kitajima, Kouki, Kleine, Thorsten, Krot, Sasha, Liu, Ming-Chang, Masuda, Yuki, Moynier, Frédéric, Nguyen, Ann, Nittler, Larry, Pack, Andreas, Park, Changkun, Piani, Laurette, Qin, Liping, Di Rocco, Tommaso, Russell, Sara S., Sakamoto, Naoya, Schönbächler, Maria, Tafla, Lauren, Tang, Haolan, Terada, Kentaro, Usui, Tomohiro, Wada, Sohei, Wadhwa, Meenakshi, Walker, Richard J., Yamashita, Katsuyuki, Yin, Qing-Zhu, Yoneda, Shigekazu, Young, Edward D., Zhang, Ai-Cheng, Nakamura, Tomoki, Naraoka, Hiroshi, Noguchi, Takaaki, Okazaki, Ryuji, Sakamoto, Kanako, Yabuta, Hikaru, Abe, Masanao, Miyazaki, Akiko, Nakato, Aiko, Nishimura, Masahiro, Okada, Tatsuaki, Yada, Toru, Yogata, Kasumi, Nakazawa, Satoru, Saiki, Takanao, Tanaka, Satoshi, Terui, Fuyuto, Tsuda, Yuichi, Watanabe, Sei-ichiro, Yoshikawa, Makoto, Tachibana, Shogo, and Yurimoto, Hisayoshi

Published
2024
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7. Pervasive aqueous alteration in the early Solar System revealed by potassium isotopic variations in Ryugu samples and carbonaceous chondrites

Author

Hu, Yan, Moynier, Frédéric, Dai, Wei, Paquet, Marine, Yokoyama, Tetsuya, Abe, Yoshinari, Aléon, Jérôme, Alexander, Conel M. O'D., Amari, Sachiko, Amelin, Yuri, Bajo, Ken-ichi, Bizzarro, Martin, Bouvier, Audrey, Carlson, Richard W., Chaussidon, Marc, Choi, Byeon-Gak, Dauphas, Nicolas, Davis, Andrew M., Di Rocco, Tommaso, Fujiya, Wataru, Fukai, Ryota, Gautam, Ikshu, Haba, Makiko K., Hibiya, Yuki, Hidaka, Hiroshi, Homma, Hisashi, Hoppe, Peter, Huss, Gary R., Ichida, Kiyohiro, Iizuka, Tsuyoshi, Ireland, Trevor R., Ishikawa, Akira, Itoh, Shoichi, Kawasaki, Noriyuki, Kita, Noriko T., Kitajima, Koki, Kleine, Thorsten, Komatani, Shintaro, Krot, Alexander N., Liu, Ming-Chang, Masuda, Yuki, Morita, Mayu, Motomura, Kazuko, Nakai, Izumi, Nagashima, Kazuhide, Nesvorný, David, Nguyen, Ann, Nittler, Larry, Onose, Morihiko, Pack, Andreas, Park, Changkun, Piani, Laurette, Qin, Liping, Russell, Sara S., Sakamoto, Naoya, Schönbächler, Maria, Tafla, Lauren, Tang, Haolan, Terada, Kentaro, Terada, Yasuko, Usui, Tomohiro, Wada, Sohei, Wadhwa, Meenakshi, Walker, Richard J., Yamashita, Katsuyuki, Yin, Qing-Zhu, Yoneda, Shigekazu, Young, Edward D., Yui, Hiroharu, Zhang, Ai-Cheng, Nakamura, Tomoki, Naraoka, Hiroshi, Noguchi, Takaaki, Okazaki, Ryuji, Sakamoto, Kanako, Yabuta, Hikaru, Abe, Masanao, Miyazaki, Akiko, Nakato, Aiko, Nishimura, Masahiro, Okada, Tatsuaki, Yada, Toru, Yogata, Kasumi, Nakazawa, Satoru, Saiki, Takanao, Tanaka, Satoshi, Terui, Fuyuto, Tsuda, Yuichi, Watanabe, Sei-ichiro, Yoshikawa, Makoto, Tachibana, Shogo, and Yurimoto, Hisayoshi

Published
2024
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8. Contribution of Ryugu-like material to Earth’s volatile inventory by Cu and Zn isotopic analysis

Author

Paquet, Marine, Moynier, Frederic, Yokoyama, Tetsuya, Dai, Wei, Hu, Yan, Abe, Yoshinari, Aléon, Jérôme, O’D. Alexander, Conel M., Amari, Sachiko, Amelin, Yuri, Bajo, Ken-ichi, Bizzarro, Martin, Bouvier, Audrey, Carlson, Richard W., Chaussidon, Marc, Choi, Byeon-Gak, Dauphas, Nicolas, Davis, Andrew M., Di Rocco, Tommaso, Fujiya, Wataru, Fukai, Ryota, Gautam, Ikshu, Haba, Makiko K., Hibiya, Yuki, Hidaka, Hiroshi, Homma, Hisashi, Hoppe, Peter, Huss, Gary R., Ichida, Kiyohiro, Iizuka, Tsuyoshi, Ireland, Trevor R., Ishikawa, Akira, Ito, Motoo, Itoh, Shoichi, Kawasaki, Noriyuki, Kita, Noriko T., Kitajima, Kouki, Kleine, Thorsten, Komatani, Shintaro, Krot, Alexander N., Liu, Ming-Chang, Masuda, Yuki, McKeegan, Kevin D., Morita, Mayu, Motomura, Kazuko, Nakai, Izumi, Nagashima, Kazuhide, Nesvorný, David, Nguyen, Ann N., Nittler, Larry, Onose, Morihiko, Pack, Andreas, Park, Changkun, Piani, Laurette, Qin, Liping, Russell, Sara S., Sakamoto, Naoya, Schönbächler, Maria, Tafla, Lauren, Tang, Haolan, Terada, Kentaro, Terada, Yasuko, Usui, Tomohiro, Wada, Sohei, Wadhwa, Meenakshi, Walker, Richard J., Yamashita, Katsuyuki, Yin, Qing-Zhu, Yoneda, Shigekazu, Young, Edward D., Yui, Hiroharu, Zhang, Ai-Cheng, Nakamura, Tomoki, Naraoka, Hiroshi, Noguchi, Takaaki, Okazaki, Ryuji, Sakamoto, Kanako, Yabuta, Hikaru, Abe, Masanao, Miyazaki, Akiko, Nakato, Aiko, Nishimura, Masahiro, Okada, Tatsuaki, Yada, Toru, Yogata, Kasumi, Nakazawa, Satoru, Saiki, Takanao, Tanaka, Satoshi, Terui, Fuyuto, Tsuda, Yuichi, Watanabe, Sei-ichiro, Yoshikawa, Makoto, Tachibana, Shogo, and Yurimoto, Hisayoshi

Published
2023
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10. Nebular history of an ultrarefractory phase bearing CAI from a reduced type CV chondrite

Author

Yoshizaki, Takashi, Nakashima, Daisuke, Nakamura, Tomoki, Park, Changkun, Sakamoto, Naoya, Ishida, Hatsumi, and Itoh, Shoichi

Subjects
Astrophysics - Earth and Planetary Astrophysics
Abstract

Ultrarefractory (UR) phases in CAIs could have formed at higher T compared to common CAI minerals and thus they potentially provide constraints on very high-T processes in the solar nebula. We report a detailed characterization of an UR phase davisite bearing CAI from a reduced type CV chondrite. Absence of secondary iron- and/or alkali-rich phases and occurrence of LIME olivine indicate that primitive chemical and isotopic compositions are preserved in the CAI. Davisite occur only in one lithological unit that consists of three chemically and isotopically distinct parts: i) $^{16}$O-poor regions with reversely-zoned melilite and davisite; ii) $^{16}$O-rich regions consisting of unzoned, gehlenitic melilite, diopside and spinel; and iii) spinel framboids composed of $^{16}$O-rich spinel and $^{16}$O-poor melilite. Random distribution of chemical and isotopic heterogeneities with sharp boundaries in the CAI indicates its formation by an aggregation of mineral assemblages formed and processed separately at different time and/or space. Although isotope exchange prior to the final agglomeration of the CAI cannot be ruled out, we suggest that modification of chemical and isotopic composition of porous CAI precursors or aggregation of isotopically distinct mineral assemblages are alternative scenarios for the origin of O-isotopic heterogeneity in CAIs. In either case, coexistence of spatially and/or temporally distinct $^{16}$O-rich and -poor gaseous reservoirs at the earliest stage of the solar system formation is required. The grain-scale oxygen isotopic disequilibrium in the CAI indicate that post-formation heating of the CAI was short, which can be achieved by rapid outward transport of the CAI. High Ti$^{3+}$/Ti$^{\mathrm{tot}}$ ratios of pyroxene and presence of LIME olivine document that the entire CAI formation process took place under highly reducing conditions., Comment: 65 pages, 15 figures

Published
2018
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11. Disequilibrium oxygen isotope distribution among aqueously altered minerals in Ryugu asteroid returned samples

Author

Kita, Noriko T., primary, Kitajima, Kouki, additional, Nagashima, Kazuhide, additional, Kawasaki, Noriyuki, additional, Sakamoto, Naoya, additional, Fujiya, Wataru, additional, Abe, Yoshinari, additional, Aléon, Jérôme, additional, Alexander, Conel M. O'D., additional, Amari, Sachiko, additional, Amelin, Yuri, additional, Bajo, Ken‐ichi, additional, Bizzarro, Martin, additional, Bouvier, Audrey, additional, Carlson, Richard W., additional, Chaussidon, Marc, additional, Choi, Byeon‐Gak, additional, Dauphas, Nicolas, additional, Davis, Andrew M., additional, Di Rocco, Tommaso, additional, Fukai, Ryota, additional, Gautam, Ikshu, additional, Haba, Makiko K., additional, Hibiya, Yuki, additional, Hidaka, Hiroshi, additional, Homma, Hisashi, additional, Hoppe, Peter, additional, Huss, Gary R., additional, Ichida, Kiyohiro, additional, Iizuka, Tsuyoshi, additional, Ireland, Trevor R., additional, Ishikawa, Akira, additional, Itoh, Shoichi, additional, Kleine, Thorsten, additional, Komatani, Shintaro, additional, Krot, Alexander N., additional, Liu, Ming‐Chang, additional, Masuda, Yuki, additional, McKeegan, Kevin D., additional, Morita, Mayu, additional, Motomura, Kazuko, additional, Moynier, Frédéric, additional, Nakai, Izumi, additional, Nguyen, Ann, additional, Nittler, Larry, additional, Onose, Morihiko, additional, Pack, Andreas, additional, Park, Changkun, additional, Piani, Laurette, additional, Qin, Liping, additional, Russell, Sara S., additional, Schönbächler, Maria, additional, Tafla, Lauren, additional, Tang, Haolan, additional, Terada, Kentaro, additional, Terada, Yasuko, additional, Usui, Tomohiro, additional, Wada, Sohei, additional, Wadhwa, Meenakshi, additional, Walker, Richard J., additional, Yamashita, Katsuyuki, additional, Yin, Qing‐Zhu, additional, Yokoyama, Tetsuya, additional, Yoneda, Shigekazu, additional, Young, Edward D., additional, Yui, Hiroharu, additional, Zhang, Ai‐Cheng, additional, Nakamura, Tomoki, additional, Naraoka, Hiroshi, additional, Noguchi, Takaaki, additional, Okazaki, Ryuji, additional, Sakamoto, Kanako, additional, Yabuta, Hikaru, additional, Abe, Masanao, additional, Miyazaki, Akiko, additional, Nakato, Aiko, additional, Nishimura, Masahiro, additional, Okada, Tatsuaki, additional, Yada, Toru, additional, Yogata, Kasumi, additional, Nakazawa, Satoru, additional, Saiki, Takanao, additional, Tanaka, Satoshi, additional, Terui, Fuyuto, additional, Tsuda, Yuichi, additional, Watanabe, Sei‐ichiro, additional, Yoshikawa, Makoto, additional, Tachibana, Shogo, additional, and Yurimoto, Hisayoshi, additional

Published
2024
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12. Author Correction: Contribution of Ryugu-like material to Earth’s volatile inventory by Cu and Zn isotopic analysis

Author

Paquet, Marine, Moynier, Frederic, Yokoyama, Tetsuya, Dai, Wei, Hu, Yan, Abe, Yoshinari, Aléon, Jérôme, O’D. Alexander, Conel M., Amari, Sachiko, Amelin, Yuri, Bajo, Ken-ichi, Bizzarro, Martin, Bouvier, Audrey, Carlson, Richard W., Chaussidon, Marc, Choi, Byeon-Gak, Dauphas, Nicolas, Davis, Andrew M., Di Rocco, Tommaso, Fujiya, Wataru, Fukai, Ryota, Gautam, Ikshu, Haba, Makiko K., Hibiya, Yuki, Hidaka, Hiroshi, Homma, Hisashi, Hoppe, Peter, Huss, Gary R., Ichida, Kiyohiro, Iizuka, Tsuyoshi, Ireland, Trevor R., Ishikawa, Akira, Ito, Motoo, Itoh, Shoichi, Kawasaki, Noriyuki, Kita, Noriko T., Kitajima, Kouki, Kleine, Thorsten, Komatani, Shintaro, Krot, Alexander N., Liu, Ming-Chang, Masuda, Yuki, McKeegan, Kevin D., Morita, Mayu, Motomura, Kazuko, Nakai, Izumi, Nagashima, Kazuhide, Nesvorný, David, Nguyen, Ann N., Nittler, Larry, Onose, Morihiko, Pack, Andreas, Park, Changkun, Piani, Laurette, Qin, Liping, Russell, Sara S., Sakamoto, Naoya, Schönbächler, Maria, Tafla, Lauren, Tang, Haolan, Terada, Kentaro, Terada, Yasuko, Usui, Tomohiro, Wada, Sohei, Wadhwa, Meenakshi, Walker, Richard J., Yamashita, Katsuyuki, Yin, Qing-Zhu, Yoneda, Shigekazu, Young, Edward D., Yui, Hiroharu, Zhang, Ai-Cheng, Nakamura, Tomoki, Naraoka, Hiroshi, Noguchi, Takaaki, Okazaki, Ryuji, Sakamoto, Kanako, Yabuta, Hikaru, Abe, Masanao, Miyazaki, Akiko, Nakato, Aiko, Nishimura, Masahiro, Okada, Tatsuaki, Yada, Toru, Yogata, Kasumi, Nakazawa, Satoru, Saiki, Takanao, Tanaka, Satoshi, Terui, Fuyuto, Tsuda, Yuichi, Watanabe, Sei-ichiro, Yoshikawa, Makoto, Tachibana, Shogo, and Yurimoto, Hisayoshi

Published
2023
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13. Formation of an ultracarbonaceous Antarctic micrometeorite through minimal aqueous alteration in a small porous icy body

Author

Yabuta, Hikaru, Noguchi, Takaaki, Itoh, Shoichi, Nakamura, Tomoki, Miyake, Akira, Tsujimoto, Shinichi, Ohashi, Noriaki, Sakamoto, Naoya, Hashiguchi, Minako, Abe, Ken-ichi, Okubo, Aya, Kilcoyne, AL David, Tachibana, Shogo, Okazaki, Ryuji, Terada, Kentaro, Ebihara, Mitsuru, and Nagahara, Hiroko

Subjects
Earth Sciences, Geology, Ultracarbonaceous Antarctic micrometeorites, Organic matter, GEMS, Aqueous alteration, Comet, Shock, SIMS, XANES, TEM, Geochemistry, Physical Geography and Environmental Geoscience, Geochemistry & Geophysics
Abstract

A comprehensive study of the organic chemistry and mineralogy of an ultracarbonaceous micrometeorite (UCAMM D05IB80) collected from near the Dome Fuji Station, Antarctica, was carried out to understand the genetic relationship among organic materials, silicates, and water. The micrometeorite is composed of a dense aggregate of ∼5 µm-sized hollow ellipsoidal organic material containing submicrometer-sized phases such as glass with embedded metal and sulfides (GEMS) and mineral grains. There is a wide area of organic material (∼15 × 15 μm) in its interior. Low-Ca pyroxene is much more abundant than olivine and shows various Mg/(Mg + Fe) ratios ranging from ∼1.0 to 0.78, which is common to previous works on UCAMMs. By contrast, GEMS grains in this UCAMM have unusual chemical compositions. They are depleted in both Mg and S, which suggests that these elements were leached out from the GEMS grains during very weak aqueous alteration, without the formation of phyllosilicates. The organic materials have two textures—smooth and globular with an irregular outline—and these are composed of imine, nitrile and/or aromatic nitrogen heterocycles, and amide. The ratio of nitrogen to carbon (N/C) in the smooth region of the organics is ∼0.15, which is five times higher than that of insoluble organic macromolecules in types 1 and 2 carbonaceous chondritic meteorites. In addition, the UCAMM organic materials are soluble in epoxy and are thus hydrophilic; this polar nature indicates that they are very primitive. The surface of the material is coated with an inorganic layer, a few nanometers thick, that consists of C, O, Si, S, and Fe. Sulfur is also contained in the interior, implying the presence of organosulfur moieties. There are no isotopic anomalies of D, 13C, or 15N in the organic material. Interstellar photochemistry alone would not be sufficient to explain the N/C ratio of the UCAMM organics; therefore, we suggest that a very small amount of fluid on a comet must have been necessary for the formation of the UCAMM. The GEMS grains depleted in Mg and S in the UCAMM prove a very weak degree of aqueous alteration; weaker than that of carbonaceous chondrites. Short-duration weak alteration probably caused by planetesimal shock locally melted cometary ice grains and released water that dissolved the organics; the fluid would likely have not mobilized because of the very low thermal conductivity of the porous icy body. This event allowed the formation of the large organic puddle of the UCAMM, as well as organic matter sulfurization, formation of thin membrane-like layers of minerals, and deformation of organic nanoglobules.

Published
2017

15. Neodymium‐142 deficits and samarium neutron stratigraphy of C‐type asteroid (162173) Ryugu

Author

Torrano, Zachary A., primary, Jordan, Michelle K., additional, Mock, Timothy D., additional, Carlson, Richard W., additional, Gautam, Ikshu, additional, Haba, Makiko K., additional, Yokoyama, Tetsuya, additional, Abe, Yoshinari, additional, Aléon, Jérôme, additional, Alexander, Conel, additional, Amari, Sachiko, additional, Amelin, Yuri, additional, Bajo, Ken‐ichi, additional, Bizzarro, Martin, additional, Bouvier, Audrey, additional, Chaussidon, Marc, additional, Choi, Byeon‐Gak, additional, Dauphas, Nicolas, additional, Davis, Andrew M., additional, Di Rocco, Tommaso, additional, Fujiya, Wataru, additional, Fukai, Ryota, additional, Hibiya, Yuki, additional, Hidaka, Hiroshi, additional, Homma, Hisashi, additional, Hoppe, Peter, additional, Huss, Gary R., additional, Ichida, Kiyohiro, additional, Iizuka, Tsuyoshi, additional, Ireland, Trevor, additional, Ishikawa, Akira, additional, Itoh, Shoichi, additional, Kawasaki, Noriyuki, additional, Kita, Noriko T., additional, Kitajima, Koki, additional, Kleine, Thorsten, additional, Komatani, Shintaro, additional, Krot, Alexander N., additional, Liu, Ming‐Chang, additional, Masuda, Yuki, additional, McKeegan, Kevin D., additional, Morita, Mayu, additional, Motomura, Kazuko, additional, Moynier, Frédéric, additional, Nakai, Izumi, additional, Nagashima, Kazuhide, additional, Nguyen, Ann, additional, Nittler, Larry, additional, Onose, Morihiko, additional, Pack, Andreas, additional, Park, Changkun, additional, Piani, Laurette, additional, Qin, Liping, additional, Russell, Sara, additional, Sakamoto, Naoya, additional, Schönbächler, Maria, additional, Tafla, Lauren, additional, Tang, Haolan, additional, Terada, Kentaro, additional, Terada, Yasuko, additional, Usui, Tomohiro, additional, Wada, Sohei, additional, Wadhwa, Meenakshi, additional, Walker, Richard J., additional, Yamashita, Katsuyuki, additional, Yin, Qing‐Zhu, additional, Yoneda, Shigekazu, additional, Young, Edward D., additional, Yui, Hiroharu, additional, Zhang, Ai‐Cheng, additional, Nakamura, Tomoki, additional, Naraoka, Hiroshi, additional, Noguchi, Takaaki, additional, Okazaki, Ryuji, additional, Sakamoto, Kanako, additional, Yabuta, Hikaru, additional, Abe, Masanao, additional, Miyazaki, Akiko, additional, Nakato, Aiko, additional, Nishimura, Masahiro, additional, Okada, Tatsuaki, additional, Yada, Toru, additional, Yogata, Kasumi, additional, Nakazawa, Satoru, additional, Saiki, Takanao, additional, Tanaka, Satoshi, additional, Terui, Fuyuto, additional, Tsuda, Yuichi, additional, Watanabe, Sei‐ichiro, additional, Yoshikawa, Makoto, additional, Tachibana, Shogo, additional, and Yurimoto, Hisayoshi, additional

Published
2023
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16. The Magnesium Isotope Composition of Samples Returned from Asteroid Ryugu

Author

Bizzarro, Martin, primary, Schiller, Martin, additional, Yokoyama, Tetsuya, additional, Abe, Yoshinari, additional, Aléon, Jérôme, additional, Alexander, Conel M. O’D., additional, Amari, Sachiko, additional, Amelin, Yuri, additional, Bajo, Ken-ichi, additional, Bouvier, Audrey, additional, Carlson, Richard W., additional, Chaussidon, Marc, additional, Choi, Byeon-Gak, additional, Dauphas, Nicolas, additional, Davis, Andrew M., additional, Di Rocco, Tommaso, additional, Fujiya, Wataru, additional, Fukai, Ryota, additional, Gautam, Ikshu, additional, Haba, Makiko K., additional, Hibiya, Yuki, additional, Hidaka, Hiroshi, additional, Homma, Hisashi, additional, Hoppe, Peter, additional, Huss, Gary R., additional, Ichida, Kiyohiro, additional, Iizuka, Tsuyoshi, additional, Ireland, Trevor R., additional, Ishikawa, Akira, additional, Itoh, Shoichi, additional, Kawasaki, Noriyuki, additional, Kita, Noriko T., additional, Kitajima, Kouki, additional, Kleine, Thorsten, additional, Komatani, Shintaro, additional, Krot, Alexander N., additional, Liu, Ming-Chang, additional, Masuda, Yuki, additional, Morita, Mayu, additional, Moynier, Fréderic, additional, Motomura, Kazuko, additional, Nakai, Izumi, additional, Nagashima, Kazuhide, additional, Nesvorný, David, additional, Nguyen, Ann, additional, Nittler, Larry, additional, Onose, Morihiko, additional, Pack, Andreas, additional, Park, Changkun, additional, Piani, Laurette, additional, Qin, Liping, additional, Russell, Sara S., additional, Sakamoto, Naoya, additional, Schönbächler, Maria, additional, Tafla, Lauren, additional, Tang, Haolan, additional, Terada, Kentaro, additional, Terada, Yasuko, additional, Usui, Tomohiro, additional, Wada, Sohei, additional, Wadhwa, Meenakshi, additional, Walker, Richard J., additional, Yamashita, Katsuyuki, additional, Yin, Qing-Zhu, additional, Yoneda, Shigekazu, additional, Young, Edward D., additional, Yui, Hiroharu, additional, Zhang, Ai-Cheng, additional, Nakamura, Tomoki, additional, Naraoka, Hiroshi, additional, Noguchi, Takaaki, additional, Okazaki, Ryuji, additional, Sakamoto, Kanako, additional, Yabuta, Hikaru, additional, Abe, Masanao, additional, Miyazaki, Akiko, additional, Nakato, Aiko, additional, Nishimura, Masahiro, additional, Okada, Tatsuaki, additional, Yada, Toru, additional, Yogata, Kasumi, additional, Nakazawa, Satoru, additional, Saiki, Takanao, additional, Tanaka, Satoshi, additional, Terui, Fuyuto, additional, Tsuda, Yuichi, additional, Watanabe, Sei-ichiro, additional, Yoshikawa, Makoto, additional, Tachibana, Shogo, additional, and Yurimoto, Hisayoshi, additional

Published
2023
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21. The Oxygen Isotopic Composition of Samples Returned from Asteroid Ryugu with Implications for the Nature of the Parent Planetesimal

Author

Tang, Haolan, primary, Young, Edward D., additional, Tafla, Lauren, additional, Pack, Andreas, additional, Di Rocco, Tommaso, additional, Abe, Yoshinari, additional, Aléon, Jérôme, additional, M. O’D. Alexander, Conel, additional, Amari, Sachiko, additional, Amelin, Yuri, additional, Bajo, Ken-ichi, additional, Bizzarro, Martin, additional, Bouvier, Audrey, additional, Carlson, Richard W., additional, Chaussidon, Marc, additional, Choi, Byeon-Gak, additional, Dauphas, Nicolas, additional, Davis, Andrew M., additional, Fujiya, Wataru, additional, Fukai, Ryota, additional, Gautam, Ikshu, additional, Haba, Makiko K., additional, Hibiya, Yuki, additional, Hidaka, Hiroshi, additional, Homma, Hisashi, additional, Hoppe, Peter, additional, Huss, Gary R., additional, Ichida, Kiyohiro, additional, Iizuka, Tsuyoshi, additional, Ireland, Trevor R., additional, Ishikawa, Akira, additional, Ito, Motoo, additional, Itoh, Shoichi, additional, Kawasaki, Noriyuki, additional, Kita, Noriko T., additional, Kitajima, Kouki, additional, Kleine, Thorsten, additional, Komatani, Shintaro, additional, Krot, Alexander N., additional, Liu, Ming-Chang, additional, Masuda, Yuki, additional, McKeegan, Kevin D., additional, Morita, Mayu, additional, Motomura, Kazuko, additional, Moynier, Frédéric, additional, Nagashima, Kazuhide, additional, Nakai, Izumi, additional, Nguyen, Ann, additional, Nittler, Larry, additional, Onose, Morihiko, additional, Park, Changkun, additional, Piani, Laurette, additional, Qin, Liping, additional, Russell, Sara S., additional, Sakamoto, Naoya, additional, Schönbächler, Maria, additional, Terada, Kentaro, additional, Terada, Yasuko, additional, Usui, Tomohiro, additional, Wada, Sohei, additional, Wadhwa, Meenakshi, additional, Walker, Richard J., additional, Yamashita, Katsuyuki, additional, Yin, Qing-Zhu, additional, Yokoyama, Tetsuya, additional, Yoneda, Shigekazu, additional, Yui, Hiroharu, additional, Zhang, Ai-Cheng, additional, Nakamura, Tomoki, additional, Naraoka, Hiroshi, additional, Noguchi, Takaaki, additional, Okazaki, Ryuji, additional, Sakamoto, Kanako, additional, Yabuta, Hikaru, additional, Abe, Masanao, additional, Miyazaki, Akiko, additional, Nakato, Aiko, additional, Nishimura, Masahiro, additional, Okada, Tatsuaki, additional, Yada, Toru, additional, Yogata, Kasumi, additional, Nakazawa, Satoru, additional, Saiki, Takanao, additional, Tanaka, Satoshi, additional, Terui, Fuyuto, additional, Tsuda, Yuichi, additional, Watanabe, Sei-ichiro, additional, Yoshikawa, Makoto, additional, Tachibana, Shogo, additional, and Yurimoto, Hisayoshi, additional

Published
2023
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27. Hydrogen Isotopic Composition of Hydrous Minerals in Asteroid Ryugu

Author

Piani, Laurette, primary, Nagashima, Kazuhide, additional, Kawasaki, Noriyuki, additional, Sakamoto, Naoya, additional, Bajo, Ken-ichi, additional, Abe, Yoshinari, additional, Aléon, Jérôme, additional, O’D. Alexander, Conel M., additional, Amari, Sachiko, additional, Amelin, Yuri, additional, Bizzarro, Martin, additional, Bouvier, Audrey, additional, Carlson, Richard W., additional, Chaussidon, Marc, additional, Choi, Byeon-Gak, additional, Dauphas, Nicolas, additional, Davis, Andrew M., additional, Di Rocco, Tommaso, additional, Fujiya, Wataru, additional, Fukai, Ryota, additional, Gautam, Ikshu, additional, Haba, Makiko K., additional, Hibiya, Yuki, additional, Hidaka, Hiroshi, additional, Homma, Hisashi, additional, Hoppe, Peter, additional, Huss, Gary R., additional, Ichida, Kiyohiro, additional, Iizuka, Tsuyoshi, additional, Ireland, Trevor R., additional, Ishikawa, Akira, additional, Itoh, Shoichi, additional, Kita, Noriko T., additional, Kitajima, Kouki, additional, Kleine, Thorsten, additional, Komatani, Shintaro, additional, Krot, Alexander N., additional, Liu, Ming-Chang, additional, Masuda, Yuki, additional, McKeegan, Kevin D., additional, Morita, Mayu, additional, Motomura, Kazuko, additional, Moynier, Frédéric, additional, Nakai, Izumi, additional, Nguyen, Ann, additional, Nittler, Larry, additional, Onose, Morihiko, additional, Pack, Andreas, additional, Park, Changkun, additional, Qin, Liping, additional, Russell, Sara S., additional, Schönbächler, Maria, additional, Tafla, Lauren, additional, Tang, Haolan, additional, Terada, Kentaro, additional, Terada, Yasuko, additional, Usui, Tomohiro, additional, Wada, Sohei, additional, Wadhwa, Meenakshi, additional, Walker, Richard J., additional, Yamashita, Katsuyuki, additional, Yin, Qing-Zhu, additional, Yokoyama, Tetsuya, additional, Yoneda, Shigekazu, additional, Young, Edward D., additional, Yui, Hiroharu, additional, Zhang, Ai-Cheng, additional, Nakamura, Tomoki, additional, Naraoka, Hiroshi, additional, Okazaki, Ryuji, additional, Sakamoto, Kanako, additional, Yabuta, Hikaru, additional, Abe, Masanao, additional, Miyazaki, Akiko, additional, Nakato, Aiko, additional, Nishimura, Masahiro, additional, Okada, Tatsuaki, additional, Yada, Toru, additional, Yogata, Kasumi, additional, Nakazawa, Satoru, additional, Saiki, Takanao, additional, Tanaka, Satoshi, additional, Terui, Fuyuto, additional, Tsuda, Yuichi, additional, Watanabe, Sei-ichiro, additional, Yoshikawa, Makoto, additional, Tachibana, Shogo, additional, and Yurimoto, Hisayoshi, additional

Published
2023
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28. Samples returned from the asteroid Ryugu are similar to Ivuna-type carbonaceous meteorites

Author

Yokoyama, Tetsuya, primary, Nagashima, Kazuhide, additional, Nakai, Izumi, additional, Young, Edward D., additional, Abe, Yoshinari, additional, Aléon, Jérôme, additional, Alexander, Conel M. O’D., additional, Amari, Sachiko, additional, Amelin, Yuri, additional, Bajo, Ken-ichi, additional, Bizzarro, Martin, additional, Bouvier, Audrey, additional, Carlson, Richard W., additional, Chaussidon, Marc, additional, Choi, Byeon-Gak, additional, Dauphas, Nicolas, additional, Davis, Andrew M., additional, Di Rocco, Tommaso, additional, Fujiya, Wataru, additional, Fukai, Ryota, additional, Gautam, Ikshu, additional, Haba, Makiko K., additional, Hibiya, Yuki, additional, Hidaka, Hiroshi, additional, Homma, Hisashi, additional, Hoppe, Peter, additional, Huss, Gary R., additional, Ichida, Kiyohiro, additional, Iizuka, Tsuyoshi, additional, Ireland, Trevor R., additional, Ishikawa, Akira, additional, Ito, Motoo, additional, Itoh, Shoichi, additional, Kawasaki, Noriyuki, additional, Kita, Noriko T., additional, Kitajima, Kouki, additional, Kleine, Thorsten, additional, Komatani, Shintaro, additional, Krot, Alexander N., additional, Liu, Ming-Chang, additional, Masuda, Yuki, additional, McKeegan, Kevin D., additional, Morita, Mayu, additional, Motomura, Kazuko, additional, Moynier, Frédéric, additional, Nguyen, Ann, additional, Nittler, Larry, additional, Onose, Morihiko, additional, Pack, Andreas, additional, Park, Changkun, additional, Piani, Laurette, additional, Qin, Liping, additional, Russell, Sara S., additional, Sakamoto, Naoya, additional, Schönbächler, Maria, additional, Tafla, Lauren, additional, Tang, Haolan, additional, Terada, Kentaro, additional, Terada, Yasuko, additional, Usui, Tomohiro, additional, Wada, Sohei, additional, Wadhwa, Meenakshi, additional, Walker, Richard J., additional, Yamashita, Katsuyuki, additional, Yin, Qing-Zhu, additional, Yoneda, Shigekazu, additional, Yui, Hiroharu, additional, Zhang, Ai-Cheng, additional, Connolly, Harold C., additional, Lauretta, Dante S., additional, Nakamura, Tomoki, additional, Naraoka, Hiroshi, additional, Noguchi, Takaaki, additional, Okazaki, Ryuji, additional, Sakamoto, Kanako, additional, Yabuta, Hikaru, additional, Abe, Masanao, additional, Arakawa, Masahiko, additional, Fujii, Atsushi, additional, Hayakawa, Masahiko, additional, Hirata, Naoyuki, additional, Hirata, Naru, additional, Honda, Rie, additional, Honda, Chikatoshi, additional, Hosoda, Satoshi, additional, Iijima, Yu-ichi, additional, Ikeda, Hitoshi, additional, Ishiguro, Masateru, additional, Ishihara, Yoshiaki, additional, Iwata, Takahiro, additional, Kawahara, Kosuke, additional, Kikuchi, Shota, additional, Kitazato, Kohei, additional, Matsumoto, Koji, additional, Matsuoka, Moe, additional, Michikami, Tatsuhiro, additional, Mimasu, Yuya, additional, Miura, Akira, additional, Morota, Tomokatsu, additional, Nakazawa, Satoru, additional, Namiki, Noriyuki, additional, Noda, Hirotomo, additional, Noguchi, Rina, additional, Ogawa, Naoko, additional, Ogawa, Kazunori, additional, Okada, Tatsuaki, additional, Okamoto, Chisato, additional, Ono, Go, additional, Ozaki, Masanobu, additional, Saiki, Takanao, additional, Sakatani, Naoya, additional, Sawada, Hirotaka, additional, Senshu, Hiroki, additional, Shimaki, Yuri, additional, Shirai, Kei, additional, Sugita, Seiji, additional, Takei, Yuto, additional, Takeuchi, Hiroshi, additional, Tanaka, Satoshi, additional, Tatsumi, Eri, additional, Terui, Fuyuto, additional, Tsuda, Yuichi, additional, Tsukizaki, Ryudo, additional, Wada, Koji, additional, Watanabe, Sei-ichiro, additional, Yamada, Manabu, additional, Yamada, Tetsuya, additional, Yamamoto, Yukio, additional, Yano, Hajime, additional, Yokota, Yasuhiro, additional, Yoshihara, Keisuke, additional, Yoshikawa, Makoto, additional, Yoshikawa, Kent, additional, Furuya, Shizuho, additional, Hatakeda, Kentaro, additional, Hayashi, Tasuku, additional, Hitomi, Yuya, additional, Kumagai, Kazuya, additional, Miyazaki, Akiko, additional, Nakato, Aiko, additional, Nishimura, Masahiro, additional, Soejima, Hiromichi, additional, Suzuki, Ayako, additional, Yada, Toru, additional, Yamamoto, Daiki, additional, Yogata, Kasumi, additional, Yoshitake, Miwa, additional, Tachibana, Shogo, additional, and Yurimoto, Hisayoshi, additional

Published
2023
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29. Analysis of Cation Composition in Dolomites on the Intact Particles Sampled from Asteroid Ryugu

Author

Morita, Mayu, Yui, Hiroharu, Urashima, Shu-hei, Onose, Morihiko, Komatani, Shintaro, Nakai, Izumi, Abe, Yoshinari, Terada, Yasuko, Homma, Hisashi, Motomura, Kazuko, Ichida, Kiyohiro, Yokoyama, Tetsuya, Nagashima, Kazuhide, Aléon, Jérôme, O’D. Alexander, Conel M., Amari, Sachiko, Amelin, Yuri, Bajo, Ken-ichi, Bizzarro, Martin, Bouvier, Audrey, Carlson, Richard W., Chaussidon, Marc, Choi, Byeon-Gak, Dauphas, Nicolas, Davis, Andrew M., Fujiya, Wataru, Fukai, Ryota, Gautam, Ikshu, Haba, Makiko K., Hibiya, Yuki, Hidaka, Hiroshi, Hoppe, Peter, Huss, Gary R., Iizuka, Tsuyoshi, Ireland, Trevor R., Ishikawa, Akira, Itoh, Shoichi, Kawasaki, Noriyuki, Kita, Noriko T., Kitajima, Kouki, Kleine, Thorsten, Krot, Sasha, Liu, Ming-Chang, Masuda, Yuki, Moynier, Frédéric, Nguyen, Ann, Nittler, Larry, Pack, Andreas, Park, Changkun, Piani, Laurette, Qin, Liping, Rocco, Tommaso Di, Russell, Sara S., Sakamoto, Naoya, Schönbächler, Maria, Tafla, Lauren, Tang, Haolan, Terada, Kentaro, Usui, Tomohiro, Wada, Sohei, Wadhwa, Meenakshi, Walker, Richard J., Yamashita, Katsuyuki, Yin, Qing-Zhu, Yoneda, Shigekazu, Young, Edward D., Zhang, Ai-Cheng, Nakamura, Tomoki, Naraoka, Hiroshi, Noguchi, Takaaki, Okazaki, Ryuji, Sakamoto, Kanako, Yabuta, Hikaru, Abe, Masanao, Miyazaki, Akiko, Nakato, Aiko, Nishimura, Masahiro, Okada, Tatsuaki, Yada, Toru, Yogata, Kasumi, Nakazawa, Satoru, Saiki, Takanao, Tanaka, Satoshi, Terui, Fuyuto, Tsuda, Yuichi, Watanabe, Sei-ichiro, Yoshikawa, Makoto, Tachibana, Shogo, and Yurimoto, Hisayoshi

Abstract

Characterization of the elemental distribution of samples with rough surfaces has been strongly desired for the analysis of various natural and artificial materials. Particularly for pristine and rare analytes with micrometer sizes embedded on specimen surfaces, non-invasive and matrix effect-free analysis is required without surface polishing treatment. To satisfy these requirements, we proposed a new method employing the sequential combination of two imaging modalities, i.e., microenergy-dispersive X-ray fluorescence (micro-XRF) and Raman micro-spectroscopy. The applicability of the developed method is tested by the quantitative analysis of cation composition in micrometer-sized carbonate grains on the surfaces of intact particles sampled directly from the asteroid Ryugu. The first step of micro-XRF imaging enabled a quick search for the sparsely scattered and micrometer-sized carbonates by the codistributions of Ca2+and Mn2+on the Mg2+- and Fe2+-rich phyllosilicate matrix. The following step of Raman micro-spectroscopy probed the carbonate grains and analyzed their cation composition (Ca2+, Mg2+, and Fe2++ Mn2+) in a matrix effect-free manner via the systematic Raman shifts of the lattice modes. The carbonates were basically assigned to ferroan dolomite bearing a considerable amount of Fe2++ Mn2+at around 10 atom %. These results are in good accordance with the assignments reported by scanning electron microscopy–energy-dispersive X-ray spectroscopy, where the thin-sectioned and surface-polished Ryugu particles were applicable. The proposed method requires neither sectioning nor surface polishing; hence, it can be applied to the remote sensing apparatus on spacecrafts and planetary rovers. Furthermore, the non-invasive and matrix effect-free characterization will provide a reliable analytical tool for quantitative analysis of the elemental distribution on the samples with surface roughness and chemical heterogeneity at a micrometer scale, such as art paintings, traditional crafts with decorated shapes, as well as sands and rocks with complex morphologies in nature.

Published
2024
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31. A super-refractory inclusion containing nonstoichiometric spinel from the CO3.0 chondrite Yamato 81020

Author

Yurimoto, Hisayoshi, Rubin, Alan E., Itoh, Shoichi, and Wasson, John T.

Abstract

We studied a unique super-refractory inclusion with a core-mantle structure from CO3.0 Yamato 81020 by secondary ion mass spectrometry, electron microprobe, and scanning electron microscope techniques. The core consists largely of hibonite and nonstoichiometric Al-rich spinel indicating formation as a liquid at an exceptionally high temperature (>1900 degrees C). The mantle consists almost entirely of melilite with gehlenitic compositions (ranging from angstrom k(2) to angstrom k(25)). The oxygen- and magnesium-isotopic compositions of the core and mantle are very different; typically, Delta O-17 (equivalent to delta O-17 - 0.52 delta O-18) similar to-26 parts per thousand and integral(Mg) (mass fractionation of Mg isotopes) similar to 10 parts per thousand/amu in the core and Delta O-17 similar to-7 parts per thousand and integral(Mg) similar to 1 parts per thousand/amu in most of the mantle. The chemical and O, Mg-isotopic data indicate that the core and mantle formed in separate events, and that the melilite now in the core was formed during the mantle-melting event, probably filling preexisting voids and surficial cavities. Analyses of core and mantle phases plot along a single Al-26-Mg-26 isochron with initial (Al-26/Al-27)(0) corresponding to 4.8 +/- 1.0 (+/- 2 sigma) x 10(-5), suggesting a similar formation age to normal CAIs in chondrites.

Published
2022

33. Contribution of Ryugu-like material to Earth’s volatile inventory by Cu and Zn isotopic analysis

Author

Paquet, Marine, primary, Moynier, Frederic, additional, Yokoyama, Tetsuya, additional, Dai, Wei, additional, Hu, Yan, additional, Abe, Yoshinari, additional, Aléon, Jérôme, additional, O’D. Alexander, Conel M., additional, Amari, Sachiko, additional, Amelin, Yuri, additional, Bajo, Ken-ichi, additional, Bizzarro, Martin, additional, Bouvier, Audrey, additional, Carlson, Richard W., additional, Chaussidon, Marc, additional, Choi, Byeon-Gak, additional, Dauphas, Nicolas, additional, Davis, Andrew M., additional, Di Rocco, Tommaso, additional, Fujiya, Wataru, additional, Fukai, Ryota, additional, Gautam, Ikshu, additional, Haba, Makiko K., additional, Hibiya, Yuki, additional, Hidaka, Hiroshi, additional, Homma, Hisashi, additional, Hoppe, Peter, additional, Huss, Gary R., additional, Ichida, Kiyohiro, additional, Iizuka, Tsuyoshi, additional, Ireland, Trevor R., additional, Ishikawa, Akira, additional, Ito, Motoo, additional, Itoh, Shoichi, additional, Kawasaki, Noriyuki, additional, Kita, Noriko T., additional, Kitajima, Kouki, additional, Kleine, Thorsten, additional, Komatani, Shintaro, additional, Krot, Alexander N., additional, Liu, Ming-Chang, additional, Masuda, Yuki, additional, McKeegan, Kevin D., additional, Morita, Mayu, additional, Motomura, Kazuko, additional, Nakai, Izumi, additional, Nagashima, Kazuhide, additional, Nesvorný, David, additional, Nguyen, Ann N., additional, Nittler, Larry, additional, Onose, Morihiko, additional, Pack, Andreas, additional, Park, Changkun, additional, Piani, Laurette, additional, Qin, Liping, additional, Russell, Sara S., additional, Sakamoto, Naoya, additional, Schönbächler, Maria, additional, Tafla, Lauren, additional, Tang, Haolan, additional, Terada, Kentaro, additional, Terada, Yasuko, additional, Usui, Tomohiro, additional, Wada, Sohei, additional, Wadhwa, Meenakshi, additional, Walker, Richard J., additional, Yamashita, Katsuyuki, additional, Yin, Qing-Zhu, additional, Yoneda, Shigekazu, additional, Young, Edward D., additional, Yui, Hiroharu, additional, Zhang, Ai-Cheng, additional, Nakamura, Tomoki, additional, Naraoka, Hiroshi, additional, Noguchi, Takaaki, additional, Okazaki, Ryuji, additional, Sakamoto, Kanako, additional, Yabuta, Hikaru, additional, Abe, Masanao, additional, Miyazaki, Akiko, additional, Nakato, Aiko, additional, Nishimura, Masahiro, additional, Okada, Tatsuaki, additional, Yada, Toru, additional, Yogata, Kasumi, additional, Nakazawa, Satoru, additional, Saiki, Takanao, additional, Tanaka, Satoshi, additional, Terui, Fuyuto, additional, Tsuda, Yuichi, additional, Watanabe, Sei-ichiro, additional, Yoshikawa, Makoto, additional, Tachibana, Shogo, additional, and Yurimoto, Hisayoshi, additional

Published
2022
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34. Ryugu’s nucleosynthetic heritage from the outskirts of the Solar System

Author

Hopp, Timo, primary, Dauphas, Nicolas, additional, Abe, Yoshinari, additional, Aléon, Jérôme, additional, O’D. Alexander, Conel M., additional, Amari, Sachiko, additional, Amelin, Yuri, additional, Bajo, Ken-ichi, additional, Bizzarro, Martin, additional, Bouvier, Audrey, additional, Carlson, Richard W., additional, Chaussidon, Marc, additional, Choi, Byeon-Gak, additional, Davis, Andrew M., additional, Di Rocco, Tommaso, additional, Fujiya, Wataru, additional, Fukai, Ryota, additional, Gautam, Ikshu, additional, Haba, Makiko K., additional, Hibiya, Yuki, additional, Hidaka, Hiroshi, additional, Homma, Hisashi, additional, Hoppe, Peter, additional, Huss, Gary R., additional, Ichida, Kiyohiro, additional, Iizuka, Tsuyoshi, additional, Ireland, Trevor R., additional, Ishikawa, Akira, additional, Ito, Motoo, additional, Itoh, Shoichi, additional, Kawasaki, Noriyuki, additional, Kita, Noriko T., additional, Kitajima, Kouki, additional, Kleine, Thorsten, additional, Komatani, Shintaro, additional, Krot, Alexander N., additional, Liu, Ming-Chang, additional, Masuda, Yuki, additional, McKeegan, Kevin D., additional, Morita, Mayu, additional, Motomura, Kazuko, additional, Moynier, Frédéric, additional, Nakai, Izumi, additional, Nagashima, Kazuhide, additional, Nesvorný, David, additional, Nguyen, Ann, additional, Nittler, Larry, additional, Onose, Morihiko, additional, Pack, Andreas, additional, Park, Changkun, additional, Piani, Laurette, additional, Qin, Liping, additional, Russell, Sara S., additional, Sakamoto, Naoya, additional, Schönbächler, Maria, additional, Tafla, Lauren, additional, Tang, Haolan, additional, Terada, Kentaro, additional, Terada, Yasuko, additional, Usui, Tomohiro, additional, Wada, Sohei, additional, Wadhwa, Meenakshi, additional, Walker, Richard J., additional, Yamashita, Katsuyuki, additional, Yin, Qing-Zhu, additional, Yokoyama, Tetsuya, additional, Yoneda, Shigekazu, additional, Young, Edward D., additional, Yui, Hiroharu, additional, Zhang, Ai-Cheng, additional, Nakamura, Tomoki, additional, Naraoka, Hiroshi, additional, Noguchi, Takaaki, additional, Okazaki, Ryuji, additional, Sakamoto, Kanako, additional, Yabuta, Hikaru, additional, Abe, Masanao, additional, Miyazaki, Akiko, additional, Nakato, Aiko, additional, Nishimura, Masahiro, additional, Okada, Tatsuaki, additional, Yada, Toru, additional, Yogata, Kasumi, additional, Nakazawa, Satoru, additional, Saiki, Takanao, additional, Tanaka, Satoshi, additional, Terui, Fuyuto, additional, Tsuda, Yuichi, additional, Watanabe, Sei-ichiro, additional, Yoshikawa, Makoto, additional, Tachibana, Shogo, additional, and Yurimoto, Hisayoshi, additional

Published
2022
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35. Presolar Stardust in Asteroid Ryugu

Author

Barosch, Jens, primary, Nittler, Larry R., additional, Wang, Jianhua, additional, O’D. Alexander, Conel M., additional, De Gregorio, Bradley T., additional, Engrand, Cécile, additional, Kebukawa, Yoko, additional, Nagashima, Kazuhide, additional, Stroud, Rhonda M., additional, Yabuta, Hikaru, additional, Abe, Yoshinari, additional, Aléon, Jérôme, additional, Amari, Sachiko, additional, Amelin, Yuri, additional, Bajo, Ken-ichi, additional, Bejach, Laure, additional, Bizzarro, Martin, additional, Bonal, Lydie, additional, Bouvier, Audrey, additional, Carlson, Richard W., additional, Chaussidon, Marc, additional, Choi, Byeon-Gak, additional, Cody, George D., additional, Dartois, Emmanuel, additional, Dauphas, Nicolas, additional, Davis, Andrew M., additional, Dazzi, Alexandre, additional, Deniset-Besseau, Ariane, additional, Di Rocco, Tommaso, additional, Duprat, Jean, additional, Fujiya, Wataru, additional, Fukai, Ryota, additional, Gautam, Ikshu, additional, Haba, Makiko K., additional, Hashiguchi, Minako, additional, Hibiya, Yuki, additional, Hidaka, Hiroshi, additional, Homma, Hisashi, additional, Hoppe, Peter, additional, Huss, Gary R., additional, Ichida, Kiyohiro, additional, Iizuka, Tsuyoshi, additional, Ireland, Trevor R., additional, Ishikawa, Akira, additional, Ito, Motoo, additional, Itoh, Shoichi, additional, Kamide, Kanami, additional, Kawasaki, Noriyuki, additional, David Kilcoyne, A. L., additional, Kita, Noriko T., additional, Kitajima, Kouki, additional, Kleine, Thorsten, additional, Komatani, Shintaro, additional, Komatsu, Mutsumi, additional, Krot, Alexander N., additional, Liu, Ming-Chang, additional, Martins, Zita, additional, Masuda, Yuki, additional, Mathurin, Jérémie, additional, McKeegan, Kevin D., additional, Montagnac, Gilles, additional, Morita, Mayu, additional, Mostefaoui, Smail, additional, Motomura, Kazuko, additional, Moynier, Frédéric, additional, Nakai, Izumi, additional, Nguyen, Ann N., additional, Ohigashi, Takuji, additional, Okumura, Taiga, additional, Onose, Morihiko, additional, Pack, Andreas, additional, Park, Changkun, additional, Piani, Laurette, additional, Qin, Liping, additional, Quirico, Eric, additional, Remusat, Laurent, additional, Russell, Sara S., additional, Sakamoto, Naoya, additional, Sandford, Scott A., additional, Schönbächler, Maria, additional, Shigenaka, Miho, additional, Suga, Hiroki, additional, Tafla, Lauren, additional, Takahashi, Yoshio, additional, Takeichi, Yasuo, additional, Tamenori, Yusuke, additional, Tang, Haolan, additional, Terada, Kentaro, additional, Terada, Yasuko, additional, Usui, Tomohiro, additional, Verdier-Paoletti, Maximilien, additional, Wada, Sohei, additional, Wadhwa, Meenakshi, additional, Wakabayashi, Daisuke, additional, Walker, Richard J., additional, Yamashita, Katsuyuki, additional, Yamashita, Shohei, additional, Yin, Qing-Zhu, additional, Yokoyama, Tetsuya, additional, Yoneda, Shigekazu, additional, Young, Edward D., additional, Yui, Hiroharu, additional, Zhang, Ai-Cheng, additional, Abe, Masanao, additional, Miyazaki, Akiko, additional, Nakato, Aiko, additional, Nakazawa, Satoru, additional, Nishimura, Masahiro, additional, Okada, Tatsuaki, additional, Saiki, Takanao, additional, Tanaka, Satoshi, additional, Terui, Fuyuto, additional, Tsuda, Yuichi, additional, Watanabe, Sei-ichiro, additional, Yada, Toru, additional, Yogata, Kasumi, additional, Yoshikawa, Makoto, additional, Nakamura, Tomoki, additional, Naraoka, Hiroshi, additional, Noguchi, Takaaki, additional, Okazaki, Ryuji, additional, Sakamoto, Kanako, additional, Tachibana, Shogo, additional, and Yurimoto, Hisayoshi, additional

Published
2022
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36. Hayabusa2 Sample Catcher and Container: Metal-Seal System for Vacuum Encapsulation of Returned Samples with Volatiles and Organic Compounds Recovered from C-Type Asteroid Ryugu

Author

Okazaki, Ryuji, Sawada, Hirotaka, Yamanouchi, Shinji, Tachibana, Shogo, Miura, Yayoi N., Sakamoto, Kanako, Takano, Yoshinori, Abe, Masanao, Itoh, Shoichi, Yamada, Keita, Yabuta, Hikaru, Okamoto, Chisato, Yano, Hajime, Noguchi, Takaaki, Nakamura, Tomoki, Nagao, Keisuke, and The Hayabusa2 SMP Team

Published
2017
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39. A Real-World Study on the Effectiveness and Safety of Pembrolizumab Plus Chemotherapy for Nonsquamous NSCLC

Author

Fujimoto, Daichi, primary, Miura, Satoru, additional, Yoshimura, Kenichi, additional, Wakuda, Kazushige, additional, Oya, Yuko, additional, Haratani, Koji, additional, Itoh, Shoichi, additional, Uemura, Takehiro, additional, Morinaga, Ryotaro, additional, Takahama, Takayuki, additional, Nakashima, Kazuhisa, additional, Tachihara, Motoko, additional, Saito, Go, additional, Tanizaki, Junko, additional, Otsubo, Kohei, additional, Ikeda, Satoshi, additional, Matsumoto, Hirotaka, additional, Hara, Satoshi, additional, Hata, Akito, additional, Masuda, Takeshi, additional, and Yamamoto, Nobuyuki, additional

Published
2022
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40. Oxygen Isotopic Compositions of Asteroidal Materials Returned from Itokawa by the Hayabusa Mission

Author

Yurimoto, Hisayoshi, Abe, Ken-ichi, Abe, Masanao, Ebihara, Mitsuru, Fujimura, Akio, Hashiguchi, Minako, Hashizume, Ko, Ireland, Trevor R., Itoh, Shoichi, Katayama, Juri, Kato, Chizu, Kawaguchi, Junichiro, Kawasaki, Noriyuki, Kitajima, Fumio, Kobayashi, Sachio, Meike, Tatsuji, Mukai, Toshifumi, Nagao, Keisuke, Nakamura, Tomoki, Naraoka, Hiroshi, Noguchi, Takaaki, Okazaki, Ryuji, Park, Changkun, Sakamoto, Naoya, Seto, Yusuke, Takei, Masashi, Tsuchiyama, Akira, Uesugi, Masayuki, Wakaki, Shigeyuki, Yada, Toru, Yamamoto, Kosuke, Yoshikawa, Makoto, and Zolensky, Michael E.

Published
2011
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43. Pembrolizumab plus chemotherapy-induced pneumonitis in chemo-naïve patients with non-squamous non-small cell lung cancer: A multicentre, retrospective cohort study

Author

Fujimoto, Daichi, primary, Miura, Satoru, additional, Yoshimura, Kenichi, additional, Wakuda, Kazushige, additional, Oya, Yuko, additional, Yokoyama, Toshihide, additional, Yokoi, Takashi, additional, Asao, Tetsuhiko, additional, Tamiya, Motohiro, additional, Nakamura, Atsushi, additional, Yoshioka, Hiroshige, additional, Haratani, Koji, additional, Teraoka, Shunsuke, additional, Tokito, Takaaki, additional, Murakami, Shuji, additional, Tamiya, Akihiro, additional, Itoh, Shoichi, additional, Yokouchi, Hiroshi, additional, Watanabe, Satoshi, additional, Yamaguchi, Ou, additional, Tomii, Keisuke, additional, and Yamamoto, Nobuyuki, additional

Published
2021
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47. Carbonate record of temporal change in oxygen fugacity and gaseous species in asteroid Ryugu

Author

Fujiya, Wataru, Kawasaki, Noriyuki, Nagashima, Kazuhide, Sakamoto, Naoya, O’D. Alexander, Conel M., Kita, Noriko T., Kitajima, Kouki, Abe, Yoshinari, Aléon, Jérôme, Amari, Sachiko, Amelin, Yuri, Bajo, Ken-ichi, Bizzarro, Martin, Bouvier, Audrey, Carlson, Richard W., Chaussidon, Marc, Choi, Byeon-Gak, Dauphas, Nicolas, Davis, Andrew M., Di Rocco, Tommaso, Fukai, Ryota, Gautam, Ikshu, Haba, Makiko K., Hibiya, Yuki, Hidaka, Hiroshi, Homma, Hisashi, Hoppe, Peter, Huss, Gary R., Ichida, Kiyohiro, Iizuka, Tsuyoshi, Ireland, Trevor R., Ishikawa, Akira, Itoh, Shoichi, Kleine, Thorsten, Komatani, Shintaro, Krot, Alexander N., Liu, Ming-Chang, Masuda, Yuki, McKeegan, Kevin D., Morita, Mayu, Motomura, Kazuko, Moynier, Frédéric, Nakai, Izumi, Nguyen, Ann, Nittler, Larry, Onose, Morihiko, Pack, Andreas, Park, Changkun, Piani, Laurette, Qin, Liping, Russell, Sara S., Schönbächler, Maria, Tafla, Lauren, Tang, Haolan, Terada, Kentaro, Terada, Yasuko, Usui, Tomohiro, Wada, Sohei, Wadhwa, Meenakshi, Walker, Richard J., Yamashita, Katsuyuki, Yin, Qing-Zhu, Yokoyama, Tetsuya, Yoneda, Shigekazu, Young, Edward D., Yui, Hiroharu, Zhang, Ai-Cheng, Nakamura, Tomoki, Naraoka, Hiroshi, Noguchi, Takaaki, Okazaki, Ryuji, Sakamoto, Kanako, Yabuta, Hikaru, Abe, Masanao, Miyazaki, Akiko, Nakato, Aiko, Nishimura, Masahiro, Okada, Tatsuaki, Yada, Toru, Yogata, Kasumi, Nakazawa, Satoru, Saiki, Takanao, Tanaka, Satoshi, Terui, Fuyuto, Tsuda, Yuichi, Watanabe, Sei-ichiro, Yoshikawa, Makoto, Tachibana, Shogo, and Yurimoto, Hisayoshi

Abstract

The Hayabusa2 spacecraft explored asteroid Ryugu and brought its surface materials to Earth. Ryugu samples resemble Ivuna-type (CI) chondrites—the most chemically primitive meteorites—and contain secondary phyllosilicates and carbonates, which are indicative of aqueous alteration. Understanding the conditions (such as temperature, redox state and fluid composition) during aqueous alteration is crucial to elucidating how Ryugu evolved to its present state, but little is known about the temporal changes in these conditions. Here we show that calcium carbonate (calcite) grains in Ryugu and Ivuna samples have variable 18O/16O and 13C/12C ratios that are, respectively, 24–46‰ and 65–108‰ greater than terrestrial standard values, whereas those of calcium–magnesium carbonate (dolomite) grains are much more homogeneous, ranging within 31–36‰ for oxygen and 67–75‰ for carbon. We infer that the calcite precipitated first over a wide range of temperatures and oxygen partial pressures, and that the proportion of gaseous CO2/CO/CH4molecules changed temporally. By contrast, the dolomite formed later in a more oxygen-rich and thus CO2-dominated environment when the system was approaching equilibrium. The characteristic isotopic compositions of secondary carbonates in Ryugu and Ivuna are not observed for other hydrous meteorites, suggesting a unique evolutionary pathway for their parent asteroid(s).

Published
2023
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