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[MZZ49-01]Prebiotic organics in samples returned from asteroid Bennu by OSIRIS-REx: a molecular inventory for the origin of life★Invited Papers
*Denise Kathleen Buckner1,2,3、José Aponte2、Jason Dworkin2、Jamie Elsila2、Yoshihiro Furukawa4、Daniel Glavin2、Hannah McLain2,3,5、Angel Mojarro2,5、Yasuhiro Oba6、Eric Parker2、Philippe Schmitt-Kopplin7,8,9、Danielle Simkus2,3,10、Harold Connolly Jr.11,12,13、Dante Lauretta12 (1.NASA Postdoctoral Program, Oak Ridge Associated Universities、2.Solar System Exploration Division, NASA Goddard Space Flight Center、3.CRESST II, NASA Goddard Space Flight Center、4.Tohoku University、5.University of Maryland Baltimore County、6.Hokkaido University、7.Max Planck Institute for Extraterrestrial Physics、8.Technical University Munich、9.Helmholtz Munich、10.Catholic University of America、11.Rowan University、12.Lunar and Planetary Laboratory, University of Arizona、13.American Museum of Natural History)
キーワード：
Bennu、Soluble organics、Carbonaceous chondrite、Sample return、Asteroid、Astrobiology
Introduction: Carbonaceous astromaterials record early Solar System processes and chemistry, including organic molecules that may have contributed to the origin of life. Meteorites lack geologic context and are exposed to terrestrial contamination, thus they are not pristine. NASA’s Origins, Spectral Interpretations, Resource Identification, Security-Regolith Explorer (OSIRIS-REx) traveled to the B-type carbonaceous asteroid (101955) Bennu and returned 121.6 g of material to Earth, offering the opportunity to study pristine astromaterials with geological context and without uncontrolled exposure to Earth’s biosphere (Lauretta and Connolly et al., 2024). Returned material includes submicron dust and rock fragments up to 3.5 cm across from at least three lithologies, formed by episodic low-temperature aqueous alteration within Bennu’s parent body (Connolly and Lauretta et al., 2025).
Results: Samples from Bennu are volatile-rich, with elevated abundances of carbon, nitrogen, and ammonia, as compared to samples from the C-type asteroid Ryugu and most meteorites (Glavin and Dworkin et al., 2025). Soluble organics of prebiotic interest in Bennu samples include amino acids (including 15 of the 20 proteinogenic species) (Mojarro et al., 2025), amines, formaldehyde, carboxylic acids, polycyclic aromatic hydrocarbons (PAHs), N-heterocycles (including all 5 nucleobases in DNA and RNA), several bioessential sugars (including ribose and glucose) (Furukawa et al., 2025), and ~16,000 chemical species consisting of C, H, N, O, S and Mg (Glavin and Dworkin et al., 2025). All free chiral amino acids are racemic within analytical errors.
Deuterium and 15N isotopic enrichments indicate some organic matter or precursors formed in a cold molecular cloud or the outer protoplanetary disk (Barnes and Nguyuen et al., 2025; Glavin and Dworkin et al., 2025), while moderate 13C isotopic values of other organics suggest parent body synthesis.
Across lithologies, the distributions of amino acids, hydrocarbons, PAH and heteroatom aromatic compound (HAC) alkylation patterns, and carboxylic acids vary in accordance with aqueous alteration, suggesting parent body synthesis (Mojarro et al., 2025).
Discussion & Conclusions: The soluble organic content measured in samples from Bennu is consistent with an extraterrestrial origin, with distributions indicating synthesis and alteration in both the interstellar medium and the parent body during episodic low-temperature aqueous processing. Bennu samples contain many essential prebiotic organics, including subcomponents of proteins, lipids, DNA, and RNA. An elevated volatile content, large 15N enrichments of ammonia and other N-containing organics, and a high abundance of N-rich isotopically anomalous compounds suggest the parent body accreted ices from a reservoir in the outer Solar System, where ammonia ice was stable. These findings expand evidence that prebiotic organics can form through numerous pathways within primitive accreting planetary bodies. Volatile-rich asteroids like Bennu could be remnants of icy bodies and a source of molecular building blocks delivered via impacts to the early Earth and other planets, potentially contributing to the origin of life.
References: Lauretta, D. S. & Connolly, H. C. Jr et al. 2024 M&PS 59, 2453-2486. Connolly, H. C. Jr & Lauretta, D. S. et al. 2025 M&PS 60, 979-996. Glavin, D. P. & Dworkin, J. et al. 2025 Nat. Astron., 9, 199–210. Barnes, J. J. & Nguyen, A. N. et al. 2025 Nat. Astron., 9(12), 1785-1802. Mojarro, A. et al. 2025 PNAS 122(49). Furukawa, Y. et al. 2025 Nat. Geo.,1-6. Sandford, S. A. et al. 2025 Nat. Astron., 1-9.
Acknowledgements: Thanks to the OSIRIS-REx Team and the Astromaterials Acquisition and Curation Office, part of the Astromaterials Research and Exploration Science (ARES) Division at NASA Johnson Space Center. This work was supported by NASA Award NNH09ZDA007O and under Contract NNM10AA11C issued through the New Frontiers Program.
Results: Samples from Bennu are volatile-rich, with elevated abundances of carbon, nitrogen, and ammonia, as compared to samples from the C-type asteroid Ryugu and most meteorites (Glavin and Dworkin et al., 2025). Soluble organics of prebiotic interest in Bennu samples include amino acids (including 15 of the 20 proteinogenic species) (Mojarro et al., 2025), amines, formaldehyde, carboxylic acids, polycyclic aromatic hydrocarbons (PAHs), N-heterocycles (including all 5 nucleobases in DNA and RNA), several bioessential sugars (including ribose and glucose) (Furukawa et al., 2025), and ~16,000 chemical species consisting of C, H, N, O, S and Mg (Glavin and Dworkin et al., 2025). All free chiral amino acids are racemic within analytical errors.
Deuterium and 15N isotopic enrichments indicate some organic matter or precursors formed in a cold molecular cloud or the outer protoplanetary disk (Barnes and Nguyuen et al., 2025; Glavin and Dworkin et al., 2025), while moderate 13C isotopic values of other organics suggest parent body synthesis.
Across lithologies, the distributions of amino acids, hydrocarbons, PAH and heteroatom aromatic compound (HAC) alkylation patterns, and carboxylic acids vary in accordance with aqueous alteration, suggesting parent body synthesis (Mojarro et al., 2025).
Discussion & Conclusions: The soluble organic content measured in samples from Bennu is consistent with an extraterrestrial origin, with distributions indicating synthesis and alteration in both the interstellar medium and the parent body during episodic low-temperature aqueous processing. Bennu samples contain many essential prebiotic organics, including subcomponents of proteins, lipids, DNA, and RNA. An elevated volatile content, large 15N enrichments of ammonia and other N-containing organics, and a high abundance of N-rich isotopically anomalous compounds suggest the parent body accreted ices from a reservoir in the outer Solar System, where ammonia ice was stable. These findings expand evidence that prebiotic organics can form through numerous pathways within primitive accreting planetary bodies. Volatile-rich asteroids like Bennu could be remnants of icy bodies and a source of molecular building blocks delivered via impacts to the early Earth and other planets, potentially contributing to the origin of life.
References: Lauretta, D. S. & Connolly, H. C. Jr et al. 2024 M&PS 59, 2453-2486. Connolly, H. C. Jr & Lauretta, D. S. et al. 2025 M&PS 60, 979-996. Glavin, D. P. & Dworkin, J. et al. 2025 Nat. Astron., 9, 199–210. Barnes, J. J. & Nguyen, A. N. et al. 2025 Nat. Astron., 9(12), 1785-1802. Mojarro, A. et al. 2025 PNAS 122(49). Furukawa, Y. et al. 2025 Nat. Geo.,1-6. Sandford, S. A. et al. 2025 Nat. Astron., 1-9.
Acknowledgements: Thanks to the OSIRIS-REx Team and the Astromaterials Acquisition and Curation Office, part of the Astromaterials Research and Exploration Science (ARES) Division at NASA Johnson Space Center. This work was supported by NASA Award NNH09ZDA007O and under Contract NNM10AA11C issued through the New Frontiers Program.