TY - JOUR

T1 - The Magnesium Isotope Composition of Samples Returned from Asteroid Ryugu

AU - Bizzarro, Martin

AU - Schiller, Martin

AU - Yokoyama, Tetsuya

AU - Abe, Yoshinari

AU - Aléon, Jérôme

AU - Alexander, Conel M. O'D.

AU - Amari, Sachiko

AU - Amelin, Yuri

AU - Bajo, Ken-ichi

AU - Bouvier, Audrey

AU - Carlson, Richard W.

AU - Chaussidon, Marc

AU - Choi, Byeon-Gak

AU - Dauphas, Nicolas

AU - Davis, Andrew M.

AU - Di Rocco, Tommaso

AU - Fujiya, Wataru

AU - Fukai, Ryota

AU - Gautam, Ikshu

AU - Haba, Makiko K.

AU - Hibiya, Yuki

AU - Hidaka, Hiroshi

AU - Homma, Hisashi

AU - Hoppe, Peter

AU - Huss, Gary R.

AU - Ichida, Kiyohiro

AU - Iizuka, Tsuyoshi

AU - Ireland, Trevor R.

AU - Ishikawa, Akira

AU - Itoh, Shoichi

AU - Kawasaki, Noriyuki

AU - Kita, Noriko T.

AU - Kitajima, Kouki

AU - Kleine, Thorsten

AU - Komatani, Shintaro

AU - Krot, Alexander N.

AU - Liu, Ming-Chang

AU - Masuda, Yuki

AU - Morita, Mayu

AU - Moynier, Fréderic

AU - Motomura, Kazuko

AU - Nakai, Izumi

AU - Nagashima, Kazuhide

AU - Nesvorný, David

AU - Nguyen, Ann

AU - Nittler, Larry

AU - Onose, Morihiko

AU - Pack, Andreas

AU - Park, Changkun

AU - Piani, Laurette

AU - Qin, Liping

AU - Russell, Sara S.

AU - Sakamoto, Naoya

AU - Schönbächler, Maria

AU - Tafla, Lauren

AU - Tang, Haolan

AU - Terada, Kentaro

AU - Terada, Yasuko

AU - Usui, Tomohiro

AU - Wada, Sohei

AU - Wadhwa, Meenakshi

AU - Walker, Richard J.

AU - Yamashita, Katsuyuki

AU - Yin, Qing-Zhu

AU - Yoneda, Shigekazu

AU - Young, Edward D.

AU - Yui, Hiroharu

AU - Zhang, Ai-Cheng

AU - Nakamura, Tomoki

AU - Naraoka, Hiroshi

AU - Noguchi, Takaaki

AU - Okazaki, Ryuji

AU - Sakamoto, Kanako

AU - Yabuta, Hikaru

AU - Abe, Masanao

AU - Miyazaki, Akiko

AU - Nakato, Aiko

AU - Nishimura, Masahiro

AU - Okada, Tatsuaki

AU - Yada, Toru

AU - Yogata, Kasumi

AU - Nakazawa, Satoru

AU - Saiki, Takanao

AU - Tanaka, Satoshi

AU - Terui, Fuyuto

AU - Tsuda, Yuichi

AU - Watanabe, Sei-ichiro

AU - Yoshikawa, Makoto

AU - Tachibana, Shogo

AU - Yurimoto, Hisayoshi

N1 - Publisher Copyright: © 2023. The Author(s). Published by the American Astronomical Society.

PY - 2023

Y1 - 2023

N2 - The nucleosynthetic isotope composition of planetary materials provides a record of the heterogeneous distribution of stardust within the early solar system. In 2020 December, the Japan Aerospace Exploration Agency Hayabusa2 spacecraft returned to Earth the first samples of a primitive asteroid, namely, the Cb-type asteroid Ryugu. This provides a unique opportunity to explore the kinship between primitive asteroids and carbonaceous chondrites. We report high-precision μ 26Mg* and μ 25Mg values of Ryugu samples together with those of CI, CM, CV, and ungrouped carbonaceous chondrites. The stable Mg isotope composition of Ryugu aliquots defines μ 25Mg values ranging from -160 ± 20 ppm to -272 ± 30 ppm, which extends to lighter compositions relative to Ivuna-type (CI) and other carbonaceous chondrite groups. We interpret the μ 25Mg variability as reflecting heterogeneous sampling of a carbonate phase hosting isotopically light Mg (μ 25Mg ∼ -1400 ppm) formed by low temperature equilibrium processes. After correcting for this effect, Ryugu samples return homogeneous μ 26Mg* values corresponding to a weighted mean of 7.1 ± 0.8 ppm. Thus, Ryugu defines a μ 26Mg* excess relative to the CI and CR chondrite reservoirs corresponding to 3.8 ± 1.1 and 11.9 ± 0.8 ppm, respectively. These variations cannot be accounted for by in situ decay of 26Al given their respective 27Al/24Mg ratios. Instead, it requires that Ryugu and the CI and CR parent bodies formed from material with a different initial 26Al/27Al ratio or that they are sourced from material with distinct Mg isotope compositions. Thus, our new Mg isotope data challenge the notion that Ryugu and CI chondrites share a common nucleosynthetic heritage.

AB - The nucleosynthetic isotope composition of planetary materials provides a record of the heterogeneous distribution of stardust within the early solar system. In 2020 December, the Japan Aerospace Exploration Agency Hayabusa2 spacecraft returned to Earth the first samples of a primitive asteroid, namely, the Cb-type asteroid Ryugu. This provides a unique opportunity to explore the kinship between primitive asteroids and carbonaceous chondrites. We report high-precision μ 26Mg* and μ 25Mg values of Ryugu samples together with those of CI, CM, CV, and ungrouped carbonaceous chondrites. The stable Mg isotope composition of Ryugu aliquots defines μ 25Mg values ranging from -160 ± 20 ppm to -272 ± 30 ppm, which extends to lighter compositions relative to Ivuna-type (CI) and other carbonaceous chondrite groups. We interpret the μ 25Mg variability as reflecting heterogeneous sampling of a carbonate phase hosting isotopically light Mg (μ 25Mg ∼ -1400 ppm) formed by low temperature equilibrium processes. After correcting for this effect, Ryugu samples return homogeneous μ 26Mg* values corresponding to a weighted mean of 7.1 ± 0.8 ppm. Thus, Ryugu defines a μ 26Mg* excess relative to the CI and CR chondrite reservoirs corresponding to 3.8 ± 1.1 and 11.9 ± 0.8 ppm, respectively. These variations cannot be accounted for by in situ decay of 26Al given their respective 27Al/24Mg ratios. Instead, it requires that Ryugu and the CI and CR parent bodies formed from material with a different initial 26Al/27Al ratio or that they are sourced from material with distinct Mg isotope compositions. Thus, our new Mg isotope data challenge the notion that Ryugu and CI chondrites share a common nucleosynthetic heritage.

U2 - 10.3847/2041-8213/ad09d9

DO - 10.3847/2041-8213/ad09d9

M3 - Journal article

AN - SCOPUS:85179467539

VL - 958

JO - The Astrophysical Journal Letters

JF - The Astrophysical Journal Letters

SN - 2041-8205

IS - 2

M1 - L25

ER -