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Accretion of the earliest inner Solar System planetesimals beyond the water snowline

Nature Astronomy volume 8, pages 290–297 (2024)Cite this article

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Abstract

How and where the first generation of inner Solar System planetesimals formed remains poorly understood. Potential formation regions are the silicate condensation line and water snowline of the solar protoplanetary disk. Whether the chemical compositions of these planetesimals align with accretion at the silicate condensation line (water-free and reduced) or water snowline (water-bearing and oxidized) is, however, unknown. Here we use the Fe/Ni and Fe/Co ratios of magmatic iron meteorites to quantify the oxidation states of the earliest planetesimals associated with non-carbonaceous (NC) and carbonaceous (CC) reservoirs, representing the inner and outer Solar System, respectively. Our results show that the earliest NC planetesimals contained substantial amounts of oxidized Fe in their mantles (3–19 wt% FeO). In turn, we argue that this required the accretion of water-bearing materials into these NC planetesimals. The presence of substantial quantities of moderately and highly volatile elements in their parent cores is also inconsistent with their accretion at the silicate condensation line and favours, instead, their formation at or beyond the water snowline. Similar oxidation states in the early formed parent bodies of NC iron meteorites and those of NC achondrites and chondrites with diverse accretion ages suggest that the formation of oxidized planetesimals from water-bearing materials was widespread in the early history of the inner Solar System.

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Fig. 1: Ni and CI-chondrite normalized bulk Ni, Co and Fe contents in the parent cores of magmatic iron meteorites.
Fig. 2: Comparison between the FeO contents and fO2 of IMPBs based on the Fe/Ni ratios of their parent cores.
Fig. 3: Variations in the oxidation states of various Solar System objects and reservoirs.

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The authors declare that the data supporting the findings of this study are available within the article and its Extended Data files.

References

  1. Kruijer, T. S. et al. Protracted core formation and rapid accretion of protoplanets. Science (1979) 344, 1150–1154 (2014).

    CAS  Google Scholar 

  2. Goldstein, J. I., Scott, E. R. D. & Chabot, N. L. Iron meteorites: crystallization, thermal history, parent bodies, and origin. Chem. der Erde 69, 293–325 (2009).

    CAS  Google Scholar 

  3. Kruijer, T. S., Burkhardt, C., Budde, G. & Kleine, T. Age of Jupiter inferred from the distinct genetics and formation times of meteorites. Proc. Natl Acad. Sci. USA 114, 6712–6716 (2017).

    ADS  CAS  PubMed  PubMed Central  Google Scholar 

  4. Spitzer, F., Burkhardt, C., Nimmo, F. & Kleine, T. Nucleosynthetic Pt isotope anomalies and the Hf-W chronology of core formation in inner and outer solar system planetesimals. Earth Planet. Sci. Lett. 576, 117211 (2021).

    CAS  Google Scholar 

  5. Youdin, A. N. & Goodman, J. Streaming instabilities in protoplanetary disks. Astrophys. J. 620, 459–469 (2005).

    ADS  Google Scholar 

  6. Cuzzi, J. N., Hogan, R. C. & Shariff, K. Toward planetesimals: dense chondrule clumps in the protoplanetary nebula. Astrophys. J. 687, 1432–1447 (2008).

    ADS  Google Scholar 

  7. Lichtenberg, T., Dra̧żkowska, J., Schönbächler, M., Golabek, G. J. & Hands, T. O. Bifurcation of planetary building blocks during Solar System formation. Science (1979) 371, 365–370 (2021).

    CAS  Google Scholar 

  8. Dra̧żkowska, J. & Dullemond, C. P. Planetesimal formation during protoplanetary disk buildup. Astron. Astrophys. 614, A62 (2018).

    ADS  Google Scholar 

  9. Izidoro, A. et al. Planetesimal rings as the cause of the Solar System’s planetary architecture. Nat. Astron. 6, 357–366 (2021).

    ADS  Google Scholar 

  10. Morbidelli, A. et al. Contemporary formation of early Solar System planetesimals at two distinct radial locations. Nat. Astron. 6, 72–79 (2021).

    ADS  Google Scholar 

  11. Dauphas, N. The isotopic nature of the Earth’s accreting material through time. Nature 541, 521–524 (2017).

    ADS  CAS  PubMed  Google Scholar 

  12. Burkhardt, C. et al. Terrestrial planet formation from lost inner solar system material. Sci. Adv. 7, 7601 (2021).

    ADS  Google Scholar 

  13. Hilton, C. D., Ash, R. D. & Walker, R. J. Chemical characteristics of iron meteorite parent bodies. Geochim. Cosmochim. Acta 318, 112–125 (2022).

    ADS  CAS  Google Scholar 

  14. Rubin, A. E. Carbonaceous and noncarbonaceous iron meteorites: differences in chemical, physical, and collective properties. Meteorit. Planet. Sci. 53, 2357–2371 (2018).

    ADS  CAS  Google Scholar 

  15. Grossman, L., Fedkin, A. V. & Simon, S. B. Formation of the first oxidized iron in the solar system. Meteorit. Planet. Sci. 47, 2160–2169 (2012).

    ADS  CAS  Google Scholar 

  16. Brearley, A. J. in Meteorites and the Early Solar System II (eds Lauretta, D. S. & McSween Jr., H. Y.) 587–624 (Univ. Arizona Press, 2006).

  17. Fedkin, A. V. & Grossman, L. Effects of dust enrichment on oxygen fugacity of cosmic gases. Meteorit. Planet. Sci. 51, 843–850 (2016).

    ADS  CAS  Google Scholar 

  18. Campbell, A. J. & Humayun, M. Compositions of group IVB iron meteorites and their parent melt. Geochim. Cosmochim. Acta 69, 4733–4744 (2005).

    ADS  CAS  Google Scholar 

  19. Zhang, B., Chabot, N. L. & Rubin, A. E. Compositions of carbonaceous-type asteroidal cores in the early solar system. Sci. Adv. 8, 5781 (2022).

    Google Scholar 

  20. Chabot, N. L. & Zhang, B. A revised trapped melt model for iron meteorites applied to the IIIAB group. Meteorit. Planet. Sci. 57, 200–227 (2022).

    ADS  CAS  PubMed  Google Scholar 

  21. Rubin, A. E., Zhang, B. & Chabot, N. L. IVA iron meteorites as late-stage crystallization products affected by multiple collisional events. Geochim. Cosmochim. Acta 331, 1–17 (2022).

    ADS  CAS  Google Scholar 

  22. Zhang, B. et al. Chemical study of group IIIF iron meteorites and the potentially related pallasites Zinder and Northwest Africa 1911. Geochim. Cosmochim. Acta 323, 202–219 (2022).

    ADS  CAS  Google Scholar 

  23. Wood, B. J., Smythe, D. J. & Harrison, T. The condensation temperatures of the elements: a reappraisal. Am. Mineral. 104, 844–856 (2019).

    ADS  Google Scholar 

  24. Steenstra, E. S., Knibbe, J. S., Rai, N. & van Westrenen, W. Constraints on core formation in Vesta from metal–silicate partitioning of siderophile elements. Geochim. Cosmochim. Acta 177, 48–61 (2016).

    ADS  CAS  Google Scholar 

  25. Wasson, J. T. & Kallemeyn, G. W. Compositions of chondrites. Philosophical Transactions of the Royal Society A: Mathematical. Phys. Eng. Sci. 325, 535–544 (1988).

    CAS  Google Scholar 

  26. Larimer, J. W. & Anders, E. Chemical fractionations in meteorites—III. Major element fractionations in chondrites. Geochim. Cosmochim. Acta 34, 367–387 (1970).

    ADS  CAS  Google Scholar 

  27. Wasson, J. T. Vesta and extensively melted asteroids: why HED meteorites are probably not from Vesta. Earth Planet. Sci. Lett. 381, 138–146 (2013).

    ADS  CAS  Google Scholar 

  28. Spitzer, F., Burkhardt, C., Budde, G., Kruijer, T. S. & Kleine, T. Isotopic evolution of the protoplanetary disk as recorded in Mo isotopes of iron meteorites. In 51st Lunar and Planetary Science Conference (LPI, 2020).

  29. Bonnand, P. & Halliday, A. N. Oxidized conditions in iron meteorite parent bodies. Nat. Geosci. 11, 401–404 (2018).

    ADS  CAS  Google Scholar 

  30. Benedix, G. K., Lauretta, D. S. & Mccoy, T. J. Thermodynamic constraints on the formation conditions of winonaites and silicate-bearing IAB irons. Geochim. Cosmochim. Acta 69, 5123–5131 (2005).

    ADS  CAS  Google Scholar 

  31. Righter, K. & Drake, M. J. Core formation in Earth’s Moon, Mars, and Vesta. Icarus 124, 513–529 (1996).

    ADS  CAS  Google Scholar 

  32. Steenstra, E. S. et al. The effect of melt composition on metal-silicate partitioning of siderophile elements and constraints on core formation in the angrite parent body. Geochim. Cosmochim. Acta 212, 62–83 (2017).

    ADS  CAS  Google Scholar 

  33. Righter, K., Sutton, S. R., Danielson, L., Pando, K. & Newville, M. Redox variations in the inner solar system with new constraints from vanadium XANES in spinels. Am. Mineral. 101, 1928–1942 (2016).

  34. Goodrich, C. A., Sutton, S. R., Wirick, S. & Jercinovic, M. J. Chromium valences in ureilite olivine and implications for ureilite petrogenesis. Geochim. Cosmochim. Acta 122, 280–305 (2013).

    ADS  CAS  Google Scholar 

  35. Hewins, R. H. & Ulmer, G. C. Intrinsic oxygen fugacities of diogenites and mesosiderite clasts. Geochim. Cosmochim. Acta 48, 1555–1560 (1984).

    ADS  CAS  Google Scholar 

  36. Schrader, D. L. & Zega, T. J. Petrographic and compositional indicators of formation and alteration conditions from LL chondrite sulfides. Geochim. Cosmochim. Acta 264, 165–179 (2019).

    ADS  CAS  PubMed  PubMed Central  Google Scholar 

  37. Righter, K. & Neff, K. E. Temperature and oxygen fugacity constraints on CK and R chondrites and implications for water and oxidation in the early solar system. Polar Sci. 1, 25–44 (2007).

    ADS  CAS  Google Scholar 

  38. Mckeown, D. A., Buechele, A. C., Tappero, R., Mccoy, T. J. & Gardner-Vandy, K. G. X-ray absorption characterization of Cr in forsterite within the MacAlpine Hills 88136 EL3 chondritic meteorite. Am. Mineral. 99, 190–197 (2014).

    ADS  CAS  Google Scholar 

  39. Steenstra, E. S. & van Westrenen, W. Geochemical constraints on core-mantle differentiation in Mercury and the aubrite parent body. Icarus 340, 113621 (2020).

    CAS  Google Scholar 

  40. Fogel, R. A. Aubrite basalt vitrophyres: the missing basaltic component and high-sulfur silicate melts. Geochim. Cosmochim. Acta 69, 1633–1648 (2005).

    ADS  CAS  Google Scholar 

  41. Weisberg, M. K. & Kimura, M. The unequilibrated enstatite chondrites. Chem. der Erde 72, 101–115 (2012).

    CAS  Google Scholar 

  42. Keil, K. Enstatite achondrite meteorites (aubrites) and the histories of their asteroidal parent bodies. Geochemistry 70, 295–317 (2010).

    CAS  Google Scholar 

  43. Wai, C. M. & Wasson, J. T. Silicon concentrations in the metal of iron meteorites. Geochim. Cosmochim. Acta 33, 1465–1471 (1969).

    ADS  CAS  Google Scholar 

  44. Pack, A., Vogel, I., Rollion-Bard, C., Luais, B. & Palme, H. Silicon in iron meteorite metal. Meteorit. Planet. Sci. 46, 1470–1483 (2011).

    ADS  CAS  Google Scholar 

  45. Sugiura, N. & Fujiya, W. Correlated accretion ages and ε 54 Cr of meteorite parent bodies and the evolution of the solar nebula. Meteorit. Planet. Sci. 49, 772–787 (2014).

    ADS  CAS  Google Scholar 

  46. Grossman, L. Condensation in the primitive solar nebula. Geochim. Cosmochim. Acta 36, 597–619 (1972).

    ADS  CAS  Google Scholar 

  47. Grossman, L., Beckett, J. R., Fedkin, A. V., Simon, S. B. & Ciesla, F. J. Redox conditions in the solar nebula: observational, experimental, and theoretical constraints. Rev. Mineral. Geochem. 68, 93–140 (2008).

    CAS  Google Scholar 

  48. Jones, R. H. Petrology and mineralogy of Type II, FeO-rich chondrules in Semarkona (LL3.0): origin by closed-system fractional crystallization, with evidence for supercooling. Geochim. Cosmochim. Acta 54, 1785–1802 (1990).

    ADS  CAS  Google Scholar 

  49. Rubin, A. E., Dunn, T. L., Garner, K., Cecchi, M. & Hernandez, M. Barred olivine chondrules in ordinary chondrites: constraints on chondrule formation. Meteorit. Planet. Sci. https://doi.org/10.1111/MAPS.14046 (2023).

    Article  Google Scholar 

  50. Schneider, J. M., Burkhardt, C., Marrocchi, Y., Brennecka, G. A. & Kleine, T. Early evolution of the solar accretion disk inferred from Cr-Ti-O isotopes in individual chondrules. Earth Planet. Sci. Lett. 551, 116585 (2020).

    CAS  Google Scholar 

  51. Palme, H. & Boynton, W. V. in Protostars and Planets III (eds Levy, E. H. & Lunine, J. I.) 979–1004 (Univ. Arizona Press, 1993).

  52. Ebel, D. S. & Grossman, L. Condensation in dust-enriched systems. Geochim. Cosmochim. Acta 64, 339–366 (2000).

    ADS  CAS  Google Scholar 

  53. Sutton, S. et al. The bulk valence state of Fe and the origin of water in chondrites. Geochim. Cosmochim. Acta 211, 115–132 (2017).

    ADS  CAS  Google Scholar 

  54. Le Guillou, C., Bernard, S., Brearley, A. J. & Remusat, L. Evolution of organic matter in Orgueil, Murchison and Renazzo during parent body aqueous alteration: In situ investigations. Geochim. Cosmochim. Acta 131, 368–392 (2014).

    ADS  Google Scholar 

  55. Alexander, C. M. O., McKeegan, K. D. & Altwegg, K. Water reservoirs in small planetary bodies: meteorites, asteroids, and comets. Space Sci. Rev. 214, 36 (2018).

    ADS  Google Scholar 

  56. Newcombe, M. E. et al. Degassing of early-formed planetesimals restricted water delivery to Earth. Nature 615, 854–857 (2023).

    ADS  CAS  PubMed  Google Scholar 

  57. Vorobyov, E. I. Variable accretion in the embedded phase of star formation. Astrophys. J. 704, 715–723 (2009).

    ADS  Google Scholar 

  58. Jørgensen, J. K., Visser, R., Williams, J. P. & Bergin, E. A. Molecule sublimation as a tracer of protostellar accretion: evidence for accretion bursts from high angular resolution C18O images. Astron. Astrophys. 579, A23 (2015).

    ADS  Google Scholar 

  59. Ciesla, F. & Lauretta, D. Radial migration and dehydration of phyllosilicates in the solar nebula. Earth Planet. Sci. Lett. 231, 1–8 (2005).

    ADS  CAS  Google Scholar 

  60. Dittrich, K., Klahr, H. & Johansen, A. Gravoturbulent planetesimal formation: the positive effect of long-lived zonal flows. Astrophys. J. 763, 117 (2013).

    ADS  Google Scholar 

  61. Lichtenberg, T. et al. A water budget dichotomy of rocky protoplanets from 26Al-heating. Nat. Astron. 3, 307–313 (2019).

    ADS  Google Scholar 

  62. Grewal, D. S., Seales, J. D. & Dasgupta, R. Internal or external magma oceans in the earliest protoplanets – Perspectives from nitrogen and carbon fractionation. Earth Planet. Sci. Lett. 598, 117847 (2022).

    CAS  Google Scholar 

  63. Grewal, D. S. & Asimow, P. D. Origin of the superchondritic carbon/nitrogen ratio of the bulk silicate Earth – an outlook from iron meteorites. Geochim. Cosmochim. Acta 344, 146–159 (2023).

    ADS  CAS  Google Scholar 

  64. Grewal, D. S., Dasgupta, R. & Marty, B. A very early origin of isotopically distinct nitrogen in inner Solar System protoplanets. Nat. Astron. 5, 356–364 (2021).

    ADS  Google Scholar 

  65. Hirschmann, M. M., Bergin, E. A., Blake, G. A., Ciesla, F. J. & Li, J. Early volatile depletion on planetesimals inferred from C–S systematics of iron meteorite parent bodies. Proc. Natl Acad. Sci. USA 118, e2026779118 (2021).

    CAS  PubMed  PubMed Central  Google Scholar 

  66. Grewal, D. S. Origin of nitrogen isotopic variations in the rocky bodies of the Solar System. Astrophys. J. 937, 123 (2022).

    ADS  Google Scholar 

  67. Grewal, D. S. et al. Limited nitrogen isotopic fractionation during core-mantle differentiation in rocky protoplanets and planets. Geochim. Cosmochim. Acta 338, 347–364 (2022).

    ADS  CAS  Google Scholar 

  68. Chabot, N. L. Sulfur contents of the parental metallic cores of magmatic iron meteorites. Geochim. Cosmochim. Acta 68, 3607–3618 (2004).

    ADS  CAS  Google Scholar 

  69. Schrader, D. L. et al. Distribution of 26Al in the CR chondrite chondrule-forming region of the protoplanetary disk. Geochim. Cosmochim. Acta 201, 275–302 (2017).

    ADS  CAS  Google Scholar 

  70. Nie, N. X. et al. Meteorites have inherited nucleosynthetic anomalies of potassium-40 produced in supernovae. Science (1979) 379, 372–376 (2023).

    CAS  Google Scholar 

  71. Tornabene, H. A., Ash, R. D., Walker, R. J. & Bermingham, K. R. Genetics, age, and crystallization history of group IC iron meteorites. Geochim. Cosmochim. Acta 340, 108–119 (2023).

    ADS  CAS  Google Scholar 

  72. Wasson, J. T., Huber, H. & Malvin, D. J. Formation of IIAB iron meteorites. Geochim. Cosmochim. Acta 71, 760–781 (2007).

    ADS  CAS  Google Scholar 

  73. Malvin, D. J., Wang, D. & Wasson, J. T. Chemical classification of iron meteorites—X. Multielement studies of 43 irons, resolution of group IIIE from IIIAB, and evaluation of Cu as a taxonomic parameter. Geochim. Cosmochim. Acta 48, 785–804 (1984).

    ADS  CAS  Google Scholar 

  74. Buchwald, V. F. Handbook of Iron Meteorites: Their History, Distribution, Composition and Structure (Univ. California Press, 1975).

  75. Jones, J. H. & Malvin, D. J. A nonmetal interaction model for the segregation of trace metals during solidification of Fe-Ni-S, Fe-Ni-P, and Fe-Ni-S-P alloys. Metall. Trans. B 21, 697–706 (1990).

    Google Scholar 

  76. Wasson, J. T. Trapped melt in IIIAB irons; solid/liquid elemental partitioning during the fractionation of the IIIAB magma. Geochim. Cosmochim. Acta 63, 2875–2889 (1999).

    ADS  CAS  Google Scholar 

  77. Wasson, J. T. Relationship between iron-meteorite composition and size: compositional distribution of irons from North Africa. Geochim. Cosmochim. Acta 75, 1757–1772 (2011).

    ADS  CAS  Google Scholar 

  78. Chabot, N. L., Wollack, E. A., McDonough, W. F., Ash, R. D. & Saslow, S. A. Experimental determination of partitioning in the Fe-Ni system for applications to modeling meteoritic metals. Meteorit. Planet. Sci. 52, 1133–1145 (2017).

    ADS  CAS  PubMed  PubMed Central  Google Scholar 

  79. Righter, K. & Drake, M. J. A magma ocean on Vesta: core formation and petrogenesis of eucrites and diogenites. Meteorit. Planet. Sci. 32, 929–944 (1997).

    ADS  CAS  Google Scholar 

  80. Namur, O., Charlier, B., Holtz, F., Cartier, C. & McCammon, C. Sulfur solubility in reduced mafic silicate melts: implications for the speciation and distribution of sulfur on Mercury. Earth Planet. Sci. Lett. 448, 102–114 (2016).

    ADS  CAS  Google Scholar 

  81. Rai, N. & Van Westrenen, W. Lunar core formation: new constraints from metal-silicate partitioning of siderophile elements. Earth Planet. Sci. Lett. 388, 343–352 (2014).

    ADS  CAS  Google Scholar 

  82. Hirschmann, M. M. Magma oceans, iron and chromium redox, and the origin of comparatively oxidized planetary mantles. Geochim. Cosmochim. Acta 328, 221–241 (2022).

    ADS  CAS  Google Scholar 

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Acknowledgements

We thank A. P. Vyas for helping to improve the clarity of our communication and we thank C. M. O’D. Alexander, G. Blake, K. Batygin and Y. Miyazaki for fruitful discussions during early stages of the research presented in this study. This study was funded by a Barr Foundation postdoctoral fellowship by Caltech awarded to D.S.G. B.Z. was supported by NASA grants 80NSSC19K1238 and 80NSSC23K0035.

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Authors and Affiliations

  1. School of Molecular Sciences, Arizona State University, Tempe, AZ, USA

    Damanveer S. Grewal

  2. School of Earth and Space Exploration, Arizona State University, Tempe, AZ, USA

    Damanveer S. Grewal

  3. Facility for Open Research in a Compressed Environment (FORCE), Arizona State University, Tempe, AZ, USA

    Damanveer S. Grewal

  4. Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA

    Damanveer S. Grewal, Nicole X. Nie & Paul D. Asimow

  5. Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA

    Nicole X. Nie

  6. Department of Earth and Space Sciences, University of California, Los Angeles, CA, USA

    Bidong Zhang

  7. Department of Earth, Environmental and Planetary Sciences, Rice University, Houston, TX, USA

    Andre Izidoro

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Contributions

D.S.G. conceived the project. D.S.G. compiled the data and performed the numerical calculations along with N.X.N. B.Z. performed the fractional crystallization calculations. A.I. helped with the astrophysical implications. All authors interpreted the data. D.S.G. wrote the manuscript with inputs from N.X.N., B.Z., A.I. and P.D.A.

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Correspondence to Damanveer S. Grewal.

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Extended data

Extended Data Fig. 1 Fractional crystallization modeling of P, Ni, Co, and Ir for group IIIE.

The Ir-Co (a), Ir-Ni (b), and P-Ni (c) models use bulk 8 wt.% S and 0.6 wt.% P. The red lines, blue lines, and green dashed lines denote solid from simple fractional crystallization (SFC solid), solid from trapped melt (TM solid), and liquid (Liquid), respectively. Ir, Co, and Ni data are from ref. 73. Phosphorus data are from ref. 74.

Extended Data Fig. 2 Comparison between the FeO contents and fO2 of IMPBs based on the Fe/Co ratios of their parent cores.

In agreement with the calculations based on Fe/Ni ratios (Fig. 2), the estimated FeO contents (a) and fO2 (b) of CC IMPBs (blue) based on Fe/Co ratios are either similar to or only modestly higher than those of NC IMPBs (red). Error bars for FeO content and fO2 represent 1σ deviation obtained by the propagation of standard deviation of individual terms in Eqs. 1 and 2, respectively (for details refer to the caption of Fig. 2).

Extended Data Fig. 3 Comparison between the FeO contents and fO2 of IMPBs based on the Fe/Ni and Fe/Co ratios of their parent cores.

The FeO contents (a) and fO2 (b) of each NC and CC IMPB, except for groups IC and IID, estimated via Fe/Ni and Fe/Co ratios of their parent cores broadly agree with each other.

Extended Data Fig. 4 Comparison between the mean FeO contents of the IMPBs based on the Fe/Ni ratios of CI and ordinary/CM chondrites.

The FeO contents of IMPBs estimated using Fe/Ni ratios of ordinary and CM chondrites (for NC and CC IMPBs, respectively) and CI chondrites are approximately similar.

Extended Data Fig. 5 Comparison between the FeO contents and fO2 of the IMPBs based on the Fe/Ni ratios determined by different fractional crystallization models.

The FeO content (a) and fO2 (b) of each NC and CC IMPB, as determined by several fractional crystallization models, broadly agree with each other. The X-axis represents FeO contents and fO2 values determined using the results from ref. 19,20,21,22, while the Y-axis represents values from ref. 13. Note that the data plotted on the X-axis are used for the discussion in this study. Data for group IC and group IIAB were not plotted since the compositions of their parent cores have only been determined in ref. 13. Additionally, data for group IIIE was not plotted as the composition of its parent core was determined only in this study.

Extended Data Fig. 6 Minimum water required to explain the FeO contents of the parent bodies of iron meteorites based on the Fe/Ni and Fe/Co ratios of their parent cores.

Although CC IMPBs generally require higher water contents than NC IMPBs to explain their FeO contents (a, b), the amount of water accreted to explain the FeO contents of NC IMPBs is also substantial.

Extended Data Table 1 Chemical compositions of the parent cores of NC and CC magmatic iron meteorites
Full size table
Extended Data Table 2 FeO contents, fO2, and minimum water contents of the parent bodies of NC and CC magmatic iron meteorites based on Fe/Ni and Fe/Co ratios of their parent cores
Full size table
Extended Data Table 3 Fe, Ni, Co, and S contents of the parent cores, and FeO contents and fO2 of the parent bodies of ungrouped magmatic iron meteorites from the NC and CC reservoirs
Full size table
Extended Data Table 4 Oxidation states of rocky bodies in the solar system
Full size table

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Grewal, D.S., Nie, N.X., Zhang, B. et al. Accretion of the earliest inner Solar System planetesimals beyond the water snowline. Nat Astron 8, 290–297 (2024). https://doi.org/10.1038/s41550-023-02172-w

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