Astrophysics and Meteorites

Nuclides of interest in astrophysical research measured by AMS ©Dominik Koll

Where do the chemical elements come from? Nuclear astrophysics is the discipline to answer this question by reproducing conditions of the early universe and stars on Earth and by establishing reliable models for nucleosynthesis of isotopes and chemical enrichment of galaxies.

Accelerator Mass Spectrometry is used to directly search for nucleosynthesis products in the form of long-lived radionuclides in geological samples. Directly related to the search in geological samples is the establishment of production rates and irradiation histories of meteorites with long-lived isotopes. Another application is the "activation + AMS" approach to determine astrophysical reaction cross-sections, complementary to online in-beam facilities.

Applications

Deep-sea ferromanganese crust from the Pacific Ocean. ©Dominik Koll

Deep-sea ferromanganese crust from the Pacific Ocean. Traces of supernova-produced 60Fe have been found in 2-3 Myr and 7 Myr old layers. r-process-synthesised interstellar 244Pu and 247Cm are under investigation with first results being positive.

Search for interstellar radionuclides produced in nearby supernovae. AMS is used for the direct detection of nucleosynthesis products on Earth. The long-lived radionuclide 60Fe (half-life of 2.6 Myr) is not abundant on Earth. It is dominantly produced in stars by stellar burning and supernovae and by cosmic-ray spallation in meteorites and cosmic dust. Searches for 60Fe in ferromanganese crusts and nodules, deep-sea sediments, lunar rock and Antarctic snow showed that there have been several interstellar 60Fe influxes in the past and continues until today. In collaboration with the AMS group of ANU at the Heavy Ion Accelerator facility in Canberra, we are successfully detecting 60Fe from recent supernovae in several samples, and this collaboration is currently the only research group world-wide capable in doing so.

Flensburg meteorite ©Addi Bischoff

Flensburg meteorite. The fall of this meteorite was observed, and it was subsequently recovered in 2019. The meteorite and its radionuclide/daughter signature were used to discover one of the oldest signatures of water in the solar system so far.

Constrain the sites of the astrophysical r-process. We also focus on the long-lived radionuclide 244Pu (half-life of 81 Myr), which is produced in the astrophysical r-process. The detection of a concomitant influx of stellar nuclides (e.g. 60Fe) and r-process nuclides (e.g. 244Pu or 247Cm) may link supernovae and the various candidates for r-process sites. The goal is to establish a history of interstellar radionuclide influxes with different half-lives as chrono-markers and different origins to understand how the solar neighbourhood was formed, how stellar explosions impact the Earth and most importantly where the heavy elements in the universe are formed.

Interstellar cloud - deposition of iron-60 in deep sea sediments. ©HZDR/Juniks/ NASA/Goddard/Adler/U.Chicago/Wesleyan

The solar neighbourhood with several dust cloudlets. The cloudlets could have been formed by supernovae and be a source of the detected 60Fe.

Irradiation histories and production rates in meteorites. The group is working on identifying and categorising meteorites by their radionuclide inventory to establish a global meteorite database. For the radionuclides 53Mn and 60Fe the group has been leading work that provided more than 2/3 of the global meteorite data. Meteorites have been used to distinguish between interstellar and interplanetary 60Fe by the knowledge of production rates of cosmogenic radionuclides. Constancy of galactic cosmic ray intensity as well as irradiation histories of single meteorites can be studied with the help of long-lived radionuclides in and out of equilibrium.

Astrophysical reaction cross-sections. Besides the direct search for nucleosynthesis products on Earth, the group works on one of the main experimental inputs for nuclear models, namely cross-sections for charged particle and neutron induced reactions. Stellar particle energies can be simulated in accelerator based irradiation facilities after the irradiation of samples. AMS is then used to determine the ratio between the seed isotope and the reaction product, which allows to determine the cross section for astrophysical environments.


User Information

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Projects and Collaborations
 
  • Joint PhD student with the Australian National University (Dominik Koll, finished 2023):
    A 10-million year time profile of interstellar influx to Earth mapped through supernova 60Fe and r-process 244Pu
    Supported by the Australian Institute of Nuclear Science and Engineering (AINSE)
  • PhD student (Sebastian Zwickel, start 2022):
    Interstellar and cosmogenic radioisotopes on the surface of the Moon
  • Collaborations with the Australian National University (for 60Fe), Australia's Nuclear Science and Technology Organisation (for 244Pu and 247Cm) and the University of Vienna (for 182Hf)
Further Reading

Fundamentals

 
  • Xilu W., Clark, A.M., Ellis, J., Ertel, A.F., Fields, B.D., Fry, B.J., Liu, Z., Miller, J.A. and Surman, R. (2021). r-Process radioisotopes from near-Earth supernovae and kilonovae. The Astrophysical Journal, 923(2), p. 219. https://doi.org/10.3847/1538-4357/ac2d90
  • Ellis, J., Fields, B.D. and Schramm, D.N. (1996). Geological isotope anomalies as signatures of nearby supernovae. The Astrophysical Journal, 470, 1227. https://doi.org/10.1086/177945

Own publications (see also here)

 
  • Wallner, A., Feige, J., Kinoshita, N., Paul, M., Fifield, L. K., Golser, R., Honda, M., Linnemann, U., Matsuzaki, H., Merchel, S., Rugel, G., Tims, S.G., Steier, P., Yamagata, T. and Winkler, S.R. (2016). Recent near-Earth supernovae probed by global deposition of interstellar radioactive 60Fe. Nature, 532, 69–72. https://doi.org/10.1038/nature17196
  • Koll, D., Korschinek, G., Faestermann, T., Gómez-Guzmán, J.M., Kipfstuhl, S., Merchel, S. and Welch, J.M. (2019). Interstellar 60Fe in Antarctica. Physical Review Letters, 123(072701). https://doi.org/10.1103/PhysRevLett.123.072701
  • Wallner, A., Froehlich, M.B., Hotchkis, M.A.C., Kinoshita, N., Paul, M., Martschini, M., Pavetich, S., Tims, S.G., Kivel, N., Schumann, D., Honda, M., Matsuzaki, H. and Yamagata, T. (2021). 60Fe and 244Pu deposited on Earth constrain the r-process yields of recent nearby supernovae. Science, 372(6543). https://doi.org/10.1126/science.aax3972
  • Bischoff, A., Alexander, C.M. O'D., Barrat, J.-A., Burkhardt, C., Busemann, H., Degering, D., Di Rocco, T., Fischer, M., Fockenberg, T., Foustoukos, D.I., Gattacceca, J., Godinho, J.R.A., Harries, D., Heinlein, D., Hellmann, J.L., Hertkorn, N., Holm, A., Jull, A.J.T., Kerraouch, I., King, A.J., Kleine, T., Koll, D., Lachner, J., Ludwig, T., Merchel, S., Mertens, C.A.K., Morino, P., Neumann, W., Pack, A., Patzek, M., Pavetich, S., Reitze, M.P., Rüfenacht, M., Rugel, G., Schmidt, C., Schmitt-Kopplin, P., Schönbächler, M., Trieloff, M., Wallner, A., Wimmer, K. and Wölfer, E. (2021). The old, unique C1 chondrite Flensburg – Insight into the first processes of aqueous alteration, brecciation, and the diversity of water-bearing parent bodies and lithologies. Geochimica et Cosmochimica Acta, 293, 142-186. https://doi.org/10.1016/j.gca.2020.10.014
  • Feige, J., Wallner, A., Fifield, L.K., Merchel, S., Rugel, G., Steier, P., Tims, S.G., Winkler, S.R. and Golser, R. (2018). Limits on 60Fe/26Al nucleosynthesis ratios from deep-sea sediment AMS measurements. Physical Review Letters 121, 221103. https://doi.org/10.1103/PhysRevLett.121.221103
  • Wallner, A., Feige, J., Fifield, L.K., Froehlich, M.B., Golser, R., Hotchkis, M.A.C., Koll, D., Leckenby, G., Martschini, M., Merchel, S., Panjkov, S., Pavetich, S., Rugel, G., Tims, S.G. (2020). 60Fe deposition during the late Pleistocene and the Holocene echoes past supernova activity. Proceedings of the National Academy of Sciences (PNAS) 201916769. https://doi.org/10.1073/pnas.1916769117