Water circulation in Ryugu asteroid affected the distribution of nucleosynthetic isotope anomalies in returned sampleOPEN ACCESS 

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

Science Advances, 8 Nov 2023, Vol 9, Issue 45

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“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 5.2−1.4+1.8Ma 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.”