The Magnesium Isotope Composition of Samples Returned from Asteroid Ryugu

Bizzarro, Martin; Schiller, Martin; Yokoyama, Tetsuya; Abe, Yoshinari; Aléon, Jérôme; Alexander, Conel M. O’D.; Amari, Sachiko; Amelin, Yuri; Bajo, Ken-ichi; 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, Kouki; Kleine, Thorsten; Komatani, Shintaro; Krot, Alexander N.; Liu, Ming-Chang; Masuda, Yuki; Morita, Mayu; Moynier, Fréderic; 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; Yurimoto, Hisayoshi

doi:10.3847/2041-8213/ad09d9

Cited by 3 publications

(1 citation statement)

References 45 publications

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“…In addition to the CR1-3 chondrites, the only carbonaceous extraterrestrial materials that contain notable amounts of water are CM, CI, and Tagish Lake (TL) chondrites as well as CI-like Ryugu samples. Particularly the CI, TL, and Ryugu samples are chemically, mineralogically, and isotopically similar to each other and more similar to the CR chondrites than all other carbonaceous samples 28 – 31 . This suggests that they might source from a common sub-reservoir that was neighboring that of the CR clan samples in the protoplanetary disk and was spatially closer to it than the CO, CK, and CV sub-reservoirs.…”

Section: Introductionmentioning

confidence: 70%

Recurrent planetesimal formation in an outer part of the early solar system

Neumann,

Ma,

Bouvier

et al. 2024

Sci Rep

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The formation of planets in our solar system encompassed various stages of accretion of planetesimals that formed in the protoplanetary disk within the first few million years at different distances to the sun. Their chemical diversity is reflected by compositionally variable meteorite groups from different parent bodies. There is general consensus that their formation location is roughly constrained by a dichotomy of nucleosynthetic isotope anomalies, relating carbonaceous (C) meteorite parent bodies to the outer protoplanetary disk and the non-carbonaceous (NC) parent bodies to an origin closer to the sun. It is a common idea, that in these inner parts of the protoplanetary disks, planetesimal accretion processes were faster. Testing such scenarios requires constraining formation ages of meteorite parent bodies. Although isotopic age dating can yield precise formation ages of individual mineral constituents of meteorites, such ages frequently represent mineral cooling ages that can postdate planetesimal formation by millions or tens of millions of years, depending on the cooling history of individual planetesimals at different depths. Nevertheless, such cooling ages provide a detailed thermal history which can be fitted by thermal evolution models that constrain the formation age of individual parent bodies. Here we apply state-of-the-art thermal evolution models to constrain planetesimal formation times particular in the outer solar system formation region of C meteorites. We infer a temporally distributed accretion of various parent bodies from $$<0.6$$ < 0.6 Ma to $$\approx 4$$ ≈ 4 Ma after solar system formation, with 3.7 Ma and $$2.5-2.75$$ 2.5 - 2.75 Ma for the parent bodies of CR1-3 chondrites and the Flensburg carbonaceous chondrite, and $$<0.6$$ < 0.6 and $$<0.7$$ < 0.7 Ma for the parent bodies of differentiated achondrites NWA 6704 and NWA 011, respectively. This implies that accretion processes in the C reservoir started as early as in the NC reservoir and were operating throughout typical protoplanetary disk lifetimes, thereby producing differentiated parent bodies with carbonaceous compositions in addition to undifferentiated C chondrite parent bodies. The accretion times correlate inversely with the degree of the meteorites’ alteration, metamorphism, or differentiation. The accretion times for the CM, CI, Ryugu, and Tafassite parent bodies of 3.8 Ma, 3.8 Ma, $$1-3$$ 1 - 3 Ma, and 1.1 Ma, respectively, fit well into this correlation in agreement with the thermal and alteration conditions suggested by these meteorites. Our results indicate that individual planetesimals formed rapidly (i.e., within $$<1$$ < 1 Ma), however, distinct planetesimals formed recurrently throughout the total lifetime of the protoplanetary disk. Rapid individual formation is consistent with streaming instabilities assisted by gravitational collapse. However, obviously not the total dust inventory was consumed at early disk evolution stages, so there must have been some delay mechanisms, e.g. collisional destruction of precursor aggregates due to high impact velocities induced by radial drift phenomena. This counterbalance enabled late ($$>2-3$$ > 2 - 3 Ma) accretion of C planetesimals beyond the snow line which escaped severe planetesimal heating and volatile loss, hence, preserving their volatiles, especially water. Only this delayed formation of water-rich planetesimals allowed Earth to accrete sufficient water to become a habitable planet, preventing it from being a bone dry planet.

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Section: Introductionmentioning

confidence: 70%

Recurrent planetesimal formation in an outer part of the early solar system

Neumann,

Ma,

Bouvier

et al. 2024

Sci Rep

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Zirconium isotope composition indicates s‐process depletion in samples returned from asteroid Ryugu

Schönbächler,

Fehr,

Yokoyama

et al. 2024

Meteorit & Planetary Scien

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Nucleosynthetic isotope variations are powerful tracers to determine genetic relationships between meteorites and planetary bodies. They can help to link material collected by space missions to known meteorite groups. The Hayabusa 2 mission returned samples from the Cb‐type asteroid (162173) Ryugu. The mineralogical, chemical, and isotopic characteristics of these samples show strong similarities to carbonaceous chondrites and in particular CI chondrites. The nucleosynthetic isotope compositions of Ryugu overlap with CI chondrites for several elements (e.g., Cr, Ti, Fe, and Zn). In contrast to these isotopes, which are of predominately supernovae origin, s‐process variations in Mo isotope data are similar to those of carbonaceous chondrites, but even more s‐process depleted. To further constrain the origin of this depletion and test whether this signature is also present for other s‐process elements, we report Zr isotope compositions for three bulk Ryugu samples (A0106, A0106‐A0107, C0108) collected from the Hayabusa 2 mission. The data are complemented with that of terrestrial rock reference materials, eucrites, and carbonaceous chondrites. The Ryugu samples are characterized by distinct 96Zr enrichment relative to Earth, indicative of a s‐process depletion. Such depletion is also observed for carbonaceous chondrites and eucrites, in line with previous Zr isotope work, but it is more extreme in Ryugu, as observed for Mo isotopes. Since s‐process Zr and Mo are coupled in mainstream SiC grains, these distinct s‐process variations might be due to SiC grain depletion in the analyzed materials, potentially caused by incomplete sample digestion, because the Ryugu samples were dissolved on a hotplate only to avoid high blank levels for other elements (e.g., Cr). However, local depletion of SiC grains cannot be excluded. An alternative, equally possible scenario is that aqueous alteration redistributed anomalous, s‐process‐depleted, Zr on a local scale, for example, into Ca‐phosphates or phyllosilicates.

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The nucleosynthetic fingerprint of the outermost protoplanetary disk and early Solar System dynamics

van Kooten,

Zhao,

Franchi

et al. 2024

Sci. Adv.

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Knowledge of the nucleosynthetic isotope composition of the outermost protoplanetary disk is critical to understand the formation and early dynamical evolution of the Solar System. We report the discovery of outer disk material preserved in a pristine meteorite based on its chemical composition, organic-rich petrology, and 15 N-rich, deuterium-rich, and 16 O-poor isotope signatures. We infer that this outer disk material originated in the comet-forming region. The nucleosynthetic Fe, Mg, Si, and Cr compositions of this material reveal that, contrary to current belief, the isotope signature of the comet-forming region is ubiquitous among outer Solar System bodies, possibly reflecting an important planetary building block in the outer Solar System. This nucleosynthetic component represents fresh material added to the outer disk by late accretion streamers connected to the ambient molecular cloud. Our results show that most Solar System carbonaceous asteroids accreted material from the comet-forming region, a signature lacking in the terrestrial planet region.

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The Magnesium Isotope Composition of Samples Returned from Asteroid Ryugu

Cited by 3 publications

References 45 publications

Recurrent planetesimal formation in an outer part of the early solar system

Recurrent planetesimal formation in an outer part of the early solar system

Zirconium isotope composition indicates s‐process depletion in samples returned from asteroid Ryugu

The nucleosynthetic fingerprint of the outermost protoplanetary disk and early Solar System dynamics

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