Precise initial abundance of Niobium-92 in the Solar System and implications for p-process nucleosynthesis

Makiko K. Haba*, Yi-Jen Lai, Jörn-Frederik Wotzlaw, Akira Yamaguchi, Maria Lugaro, Maria Schönbächler

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    14 Citations (Scopus)


    The niobium-92–zirconium-92 (92Nb–92Zr) decay system with a half-life of 37 Ma has great potential to date the evolution of planetary materials in the early Solar System. Moreover, the initial abundance of the p-process isotope 92Nb in the Solar System is important for quantifying the contribution of p-process nucleosynthesis in astrophysical models. Current estimates of the initial 92Nb/93Nb ratios have large uncertainties compromising the use of the 92Nb–92Zr cosmochronometer and leaving nucleosynthetic models poorly constrained. Here, the initial 92Nb abundance is determined to high precision by combining the 92Nb–92Zr systematics of cogenetic rutiles and zircons from mesosiderites with U–Pb dating of the same zircons. The mineral pair indicates that the 92Nb/93Nb ratio of the Solar System started with (1.66 ± 0.10) × 10−5, and their 92Zr/90Zr ratios can be explained by a three-stage Nb–Zr evolution on the mesosiderite parent body. Because of the improvement by a factor of 6 of the precision of the initial Solar System 92Nb/93Nb, we can show that the presence of 92Nb in the early Solar System provides further evidence that both type Ia supernovae and core-collapse supernovae contributed to the light p-process nuclei.
    Original languageEnglish
    Article numbere2017750118
    Pages (from-to)1-7
    Number of pages7
    JournalProceedings of the National Academy of Sciences of the United States of America
    Issue number8
    Publication statusPublished - 23 Feb 2021


    • Niobium-92
    • short-lived radionuclide
    • Zr isotopes
    • mesosiderite
    • p-process nucleosynthesis


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