¹Eric T. Parker et al. (>10)
Geochimica et Cosmochimica Acta (in Press) Link to Article [https://doi.org/10.1016/j.gca.2023.02.017]
¹Astrobiology Analytical Laboratory, Solar System Exploration Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771, U.S.A
Copyright Elsevier

The hot water and acid extracts of two different Ryugu samples collected by the Hayabusa2 mission were analyzed for the presence of aliphatic amines and amino acids. The abundances and relative distributions of both classes of molecules were determined, as well as the enantiomeric compositions of the chiral amino acids. The Ryugu samples studied here were recovered from sample chambers A and C, which were composed of surface material, and a combination of surface and possible subsurface material, respectively. A total of thirteen amino acids were detected and quantitated in these samples, with an additional five amino acids that were tentatively identified but not quantitated. The abundances of four aliphatic amines identified in the Ryugu samples were also determined in the current work. Amino acids were observed in the acid hydrolyzed and unhydrolyzed hot water extracts of asteroid Ryugu regolith using liquid chromatography with UV fluorescence detection and high-resolution mass spectrometry. Conversely, aliphatic amines were only analyzed in the unhydrolyzed hot water Ryugu extracts. Two- to six-carbon (C2-C6) amino acids with individual abundances ranging from 0.02–15.8 nmol g-1, and one- to three-carbon (C1-C3) aliphatic amines with individual abundances from 0.05–34.14 nmol g-1, were found in the hot water extracts. Several non-protein amino acids that are rare in biology, including β-amino-n-butyric acid (β-ABA) and β-aminoisobuytric acid (β-AIB), were racemic or very nearly racemic, thus indicating their likely abiotic origins. Trace amounts of select protein amino acids that were enriched in the l-enantiomer may indicate low levels of terrestrial amino acid contamination in the samples. However, the presence of elevated abundances of free and racemic alanine, a common protein amino acid in terrestrial biology, and elevated abundances of the predominately free and racemic non-protein amino acids, β-ABA and β-AIB, indicate that many of the amino acids detected in the Ryugu water extracts were indigenous to the samples. Although the Ryugu samples have been found to be chemically similar to CI type carbonaceous chondrites, the measured concentrations and relative distributions of amino acids and aliphatic amines in Ryugu samples were notably different from those previously observed for the CI1.1 carbonaceous chondrite, Orgueil. This discrepancy could be the result of differences in the original chemical compositions of the parent bodies and/or alteration conditions, such as space weathering. In addition to α-amino acids that could have been formed by Strecker cyanohydrin synthesis during a low temperature aqueous alteration phase, β-, γ-, and δ-amino acids, including C3 – C5 straight-chain n-ω-amino acids that are not formed by Strecker synthesis, were also observed in the Ryugu extracts. The suite of amino acids measured in the Ryugu samples indicates that multiple amino acid formation mechanisms were active on the Ryugu parent body. The analytical techniques used here are well-suited to search for similar analytes in asteroid Bennu material collected by the NASA OSIRIS-REx mission scheduled for Earth return in September 2023.

¹Tetsuya Yokoyama et al. (>10)
Science 379, 6634 Link to Article [DOI: 10.1126/science.abn78]
¹Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Tokyo 152-8551, Japan.
Reprinted with permission from AAAS

Carbonaceous meteorites are thought to be fragments of C-type (carbonaceous) asteroids. Samples of the C-type asteroid (162173) Ryugu were retrieved by the Hayabusa2 spacecraft. We measured the mineralogy and bulk chemical and isotopic compositions of Ryugu samples. The samples are mainly composed of materials similar to those of carbonaceous chondrite meteorites, particularly the CI (Ivuna-type) group. The samples consist predominantly of minerals formed in aqueous fluid on a parent planetesimal. The primary minerals were altered by fluids at a temperature of 37° ± 10°C, about 5.2+0.8−0.7 million (statistical) or 5.2+1.6−2.1
million (systematic) years after the formation of the first solids in the Solar System. After aqueous alteration, the Ryugu samples were likely never heated above ~100°C. The samples have a chemical composition that more closely resembles that of the Sun’s photosphere than other natural samples do.

¹Ryuji Okazaki et al. (>10)
Science 379, 6634 Link to Article [DOI: 10.1126/science.abo0431]
¹Department of Earth and Planetary Sciences, Kyushu University, Fukuoka 819-0395, Japan.
Reprinted with permission AAAS

The near-Earth carbonaceous asteroid (162173) Ryugu is expected to contain volatile chemical species that could provide information on the origin of Earth’s volatiles. Samples of Ryugu were retrieved by the Hayabusa2 spacecraft. We measured noble gas and nitrogen isotopes in Ryugu samples and found that they are dominated by presolar and primordial components, incorporated during Solar System formation. Noble gas concentrations are higher than those in Ivuna-type carbonaceous (CI) chondrite meteorites. Several host phases of isotopically distinct nitrogen have different abundances among the samples. Our measurements support a close relationship between Ryugu and CI chondrites. Noble gases produced by galactic cosmic rays, indicating a ~5 million year exposure, and from implanted solar wind record the recent irradiation history of Ryugu after it migrated to its current orbit.

¹T.Nakamura et al. (>10)
Science 379, 6634 Link to Article [DOI: 10.1126/science.abn86]
¹Department of Earth Sciences, Tohoku University, Sendai 980-8578, Japan.
Reprinted with permission from AAAS

Samples of the carbonaceous asteroid Ryugu were brought to Earth by the Hayabusa2 spacecraft. We analyzed 17 Ryugu samples measuring 1 to 8 millimeters. Carbon dioxide–bearing water inclusions are present within a pyrrhotite crystal, indicating that Ryugu’s parent asteroid formed in the outer Solar System. The samples contain low abundances of materials that formed at high temperatures, such as chondrules and calcium- and aluminum-rich inclusions. The samples are rich in phyllosilicates and carbonates, which formed through aqueous alteration reactions at low temperature, high pH, and water/rock ratios of <1 (by mass). Less altered fragments contain olivine, pyroxene, amorphous silicates, calcite, and phosphide. Numerical simulations, based on the mineralogical and physical properties of the samples, indicate that Ryugu’s parent body formed ~2 million years after the beginning of Solar System formation.

¹Srivastava, Y. et al. (>10)
Current Science 124, 152-154 Link to Article [ISSN 00113891]
¹Physical Research Laboratory, Ahmedabad, 380 009, India

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¹Brent D. Turrin,²Fara Lindsay,¹Jeremy S. Delaney,^2,3,4Jisun Park,²Gregory F. Herzog,¹Carl Swisher Jr,⁵Cyrena A. Goodrich
Meteoritics & Planetary Science (in Press) Open Access Link to Article [https://doi.org/10.1111/maps.13953]
¹Department of Earth and Planetary Sciences, Rutgers University, Piscataway, New Jersey, 08854 USA
²Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey, 08854 USA
³Physical Sciences, Kingsborough Community College of the City University of New York, Brooklyn, New York, 11235 USA
⁴Department of Earth and Planetary Sciences, American Museum of Natural History, New York, New York, 10024 USA
⁵Lunar and Planetary Institute, Universities Space Research Association, Houston, Texas, 77058 USA
Published by arrangement with John Wiley & Sons

The Almahata Sitta (AhS) meteorite consists of disaggregated clasts from the impact of the polymict asteroid 2008 TC3, including ureilitic (70%–80%) and diverse non-ureilitic materials. We determined the 40Ar/39Ar release patterns for 16 AhS samples (3–1500 μg) taken from three chondritic clasts, AhS 100 (L4), AhS 25 (H5), and MS-D (EL6), as well as a clast of ureilitic trachyandesite MS-MU-011, also known as ALM-A, which is probably a sample of the crust of the ureilite parent body (UPB). Based on our analyses, best estimates of the 40Ar/39Ar ages (Ma) of the chondritic clasts are 4535 ± 10 (L4), 4537–4555 with a younger age preferred (H5), and 4513 ± 17 (EL6). The ages for the L4 and the H5 clasts are older than the most published 40Ar/39Ar ages for L4 and H5 meteorites, respectively. The age for the EL6 clast is typical of older EL6 chondrites. These ages indicate times of argon closure ranging up to 50 Ma after the main constituents of the host breccia, that is, the ureilitic components of AhS, reached the >800°C blocking temperatures of pyroxene and olivine thermometers. We suggest that these ages record the times at which the clasts cooled to the Ar closure temperatures on their respective parent bodies. This interpretation is consistent with the recent proposal that the majority of xenolithic materials in polymict ureilites were implanted into regolith 40–60 Ma after calcium–aluminum-rich inclusion and is consistent with the interpretation that 2008 TC3 was a polymict ureilite. With allowance for its 10-Ma uncertainty, the 4549-Ma 40Ar/39Ar age of ALM-A is consistent with closure within a few Ma of the time recorded by its Pb/Pb age either on the UPB or as part of a rapidly cooling fragment. Plots of age versus cumulative 39Ar release for 10 of 15 samples with ≥5 heating steps indicate minor losses of 40Ar over the last 4.5 Ga. The other five such samples lost some 40Ar at estimated times no earlier than 3800–4500 Ma bp. Clustering of ages in the low-temperature data for these five samples suggests that an impact caused localized heating of the AhS progenitor ~2.7 Ga ago. In agreement with the published work, 10 estimates of cosmic-ray exposure ages based on 38Ar concentrations average 17 ± 5 Ma but may include some early irradiation.

¹Moromoto, Narumi,^1,2Kawai, Yosuke,^1,2Terada, Kentaro,³Miyahara, Masaaki, ⁴Takahata, Naoto,^4,5Sano, Yuji,³Fujikawa, Naoko,^6,7Anand, Mahesh
Mass Spectrometry 12, A0115 Open Access Link to Article [DOI 10.5702/massspectrometry.A0115]
¹Department of Earth and Space Science, Graduate School of Science, Osaka University, 1–1 Machikaneyama, Osaka, Toyonaka, 560–0043, Japan
²Forefront Research Center, Graduate School of Science, Osaka University, 1–1 Machikaneyama, Osaka, Toyonaka, 560–0043, Japan
³Graduate School of Advanced Science and Engineering, Hiroshima University, Hiroshima, Higashi-Hiroshima, 739–8526, Japan
⁴Atmosphere and Ocean Research Institute, The University of Tokyo, Chiba, Kashiwa, 277–8564, Japan
⁵Center for Advanced Marine Core Research, Kochi University, Kochi, Nankoku, 783–8502, Japan
⁶School of Physical Sciences, The Open University, Milton Keynes, MK7 6AA, United Kingdom
⁷Department of Earth Sciences, The Natural History Museum, London, SW7 5BD, United Kingdom

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^1,2J.N. Rasera,¹J.J. Cilliers,²J.-A. Lamamy,^1,3K. Hadler
Planetary and Space Science (in Press) Link to Article [https://doi.org/10.1016/j.pss.2023.105651]
¹Department of Earth Sciences and Engineering, Imperial College London, Exhibition Road, London, SW7 2AZ, United Kingdom
²ispace Europe S.A, 5, rue de l’Industrie, L-1811, Luxembourg City, Luxembourg
³European Space Resources Innovation Centre (ESRIC), Luxembourg Institute of Science and Technology (LIST), Maison de l’Innovation, 5, avenue des Hauts-Fourneuax, L-4362, Esch-sur-Alzette, Luxembourg

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¹Bittaru, Ilaria et al. (>10)
Applied Radiation and Isotopes 194, 110651 Link to Article [DOI 10.1016/j.apradiso.2023.110651]
¹Universitá degli Studi di Torino, Via Pietro Giuria 1, Torino, 10125, Italy

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¹Tahir, Naeem Ahmad,¹Bagnoud, Vincent,¹Neumayer, Paul,²Piriz, Antonio Roberto,²Piriz, Sofia Ayelen
Scientific Reports 13, 1459 Open Access Link to Article [DOI 10.1038/s41598-023-28709-7]
¹GSI Helmholtzzentrum für Schwerionenforschung, Planckstraße 1, Darmstadt, 64291, Germany
²E.T.S.I. Industriales, Universidad de Castilla-La Mancha, Ciudad Real, 13071, Spain

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