ABSTRACT The samples returned from asteroid Ryugu were collected both at its surface and at its subsurface by Hayabusa2 and can, thus, provide information on the space weathering of C-type

asteroids at different depths without terrestrial contamination. The near-infrared hyperspectral microscope MicrOmega gathered data on the –OH feature at ~2.7 μm for 177 individual grains

from the two collection sites. Here, through a spectral analysis of these data, we show that the position of the band peak can be used as an indicator of the degree of space weathering. Most

subsurficial grains do not present space weathering features, indicating that Ryugu’s subsurface layers have never been exposed to the interplanetary medium. Moreover, the ~2.7 μm feature

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OTHERS CONSTRAINTS ON SOLAR SYSTEM EARLY EVOLUTION BY MICROMEGA ANALYSIS OF RYUGU CARBONATES Article 12 January 2023 FIRST COMPOSITIONAL ANALYSIS OF RYUGU SAMPLES BY THE MICROMEGA

HYPERSPECTRAL MICROSCOPE Article 20 December 2021 PRELIMINARY ANALYSIS OF THE HAYABUSA2 SAMPLES RETURNED FROM C-TYPE ASTEROID RYUGU Article Open access 20 December 2021 DATA AVAILABILITY The

average spectrum of each grain assessed in this study is available from the Ryugu Sample Database System (JAXA) at https://darts.isas.jaxa.jp/curation/hayabusa2/. Source data are provided

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AUTHOR INFORMATION AUTHORS AND AFFILIATIONS * Institut d’Astrophysique Spatiale, Université Paris-Saclay, CNRS, Orsay, France T. Le Pivert-Jolivet, R. Brunetto, C. Pilorget, J.-P. Bibring, 

V. Hamm, C. Lantz, D. Loizeau, L. Riu, D. Baklouti, F. Poulet, A. Aléon-Toppani, J. Carter & Y. Langevin * Institut Universitaire de France, Paris, France C. Pilorget * Institute of

Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Japan A. Nakato, K. Hatakeda, K. Yogata, T. Okada, T. Yada, Y. Hitomi, K. Kumagai, A. Miyazaki, K. Nagashima,

 M. Nishimura, T. Usui, M. Abe, T. Saiki, S. Tanaka, S. Nakazawa & Y. Tsuda * Marine Works Japan, Ltd., Yokosuka, Japan K. Hatakeda, Y. Hitomi & K. Kumagai * ESAC, ESA, Madrid, Spain

L. Riu * University of Tokyo, Bunkyo, Tokyo, Japan T. Okada * The Graduate University for Advanced Studies (SOKENDAI), Hayama, Japan M. Abe, S. Tanaka & Y. Tsuda * University of Tokyo,

Kashiwa, Japan S. Tanaka * Nagoya University, Nagoya, Japan S. Watanabe Authors * T. Le Pivert-Jolivet View author publications You can also search for this author inPubMed Google Scholar *

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Scholar CONTRIBUTIONS R.B., C.P., J.-P.B., A.N., V.H., K.H., D.L., L.R., K.Y., T.O., T.Y., T.U., M.A., T.S., S.T., S.N., Y.T. and S.W. conceived and designed the experiments. T.L.P.-J.,

R.B., C.P., J.-P.B., A.N., K.H., C.L., D.L., L.R., K.Y., T.O., T.Y., Y.H., K.K., A.M., K.N. and M.N. performed the experiments. T.L.P.-J., R.B., C.P., J.-P.B., A.N., C.L., D.L., L.R., D.B.,

F.P., A.A.-T., J.C. and Y.L. analysed the data. T.L.P.-J., R.B., C.P., A.N., V.H., K.H., C.L., D.L., L.R. and K.Y. contributed materials and analysis tools. T.L.P.-J., R.B., C.P., J.-P.B.,

A.N., C.L., L.R., D.B., F.P. and T.O. wrote, discussed and commented on the paper. CORRESPONDING AUTHOR Correspondence to T. Le Pivert-Jolivet. ETHICS DECLARATIONS COMPETING INTERESTS The

authors declare no competing interests. PEER REVIEW PEER REVIEW INFORMATION _Nature Astronomy_ thanks the anonymous reviewers for their contribution to the peer review of this work.

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SUPPLEMENTARY INFORMATION Supplementary Figs. 1–17 and Tables 1–4. SOURCE DATA SOURCE DATA FIG. 2 Table of peak positions and band depths for all grains assessed in this study. SOURCE DATA

FIG. 4 Table of peak positions and band depths for all grains assessed in this study. SOURCE DATA FIG. 5 Table of peak positions and band depths for all grains assessed in this study. RIGHTS

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permissions ABOUT THIS ARTICLE CITE THIS ARTICLE Le Pivert-Jolivet, T., Brunetto, R., Pilorget, C. _et al._ Space weathering record and pristine state of Ryugu samples from MicrOmega

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