Digging in the Dirt: The Search for Supernova 60Fe in the Microfossil Record
Within the Universe, the production of 60Fe is limited to two sites: in massive stars which end their lives as Type II core collapse supernovae; and Type 1a supernovae, which are the result of a thermonuclear runaway in the core of a white dwarf. Radioactive 60Fe has a half life of 2.62 Myr. This half life is short compared to the lifetimes of most stars, but it is also long enough compared to the time scale required for its production within stars. Thus, this nuclide serves as an active "tracer isotope" for ongoing galactic nucleosynthesis. It also serves as a proxy for past supernova activity. Using the techniques of accelerator mass spectrometry (AMS), live atoms of 60Fe have been previously discovered within a deep-sea ferromanganese crust, proving that our planet has been exposed to the debris of a past (but, fortunately, not too close) supernova. In this talk I will describe the astrophysics of 60Fe production, outline the past 60Fe discovery and AMS. From these, I will then describe our search for supernova 60Fe in the magnetosome microfossil record. This project is a collaboration between members of the nuclear astrophysics group at TUM, the geophysics faculty at LMU and the microbiology faculty of LMU.
https://www.munich-geocenter.org/events/seminars/lunchtime-seminar-6/digging-in-the-dirt-the-search-for-supernova-60fe
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Digging in the Dirt: The Search for Supernova 60Fe in the Microfossil Record
Abstract
Within the Universe, the production of 60Fe is limited to two sites: in massive stars which end their lives as Type II core collapse supernovae; and Type 1a supernovae, which are the result of a thermonuclear runaway in the core of a white dwarf. Radioactive 60Fe has a half life of 2.62 Myr. This half life is short compared to the lifetimes of most stars, but it is also long enough compared to the time scale required for its production within stars. Thus, this nuclide serves as an active "tracer isotope" for ongoing galactic nucleosynthesis. It also serves as a proxy for past supernova activity. Using the techniques of accelerator mass spectrometry (AMS), live atoms of 60Fe have been previously discovered within a deep-sea ferromanganese crust, proving that our planet has been exposed to the debris of a past (but, fortunately, not too close) supernova. In this talk I will describe the astrophysics of 60Fe production, outline the past 60Fe discovery and AMS. From these, I will then describe our search for supernova 60Fe in the magnetosome microfossil record. This project is a collaboration between members of the nuclear astrophysics group at TUM, the geophysics faculty at LMU and the microbiology faculty of LMU.
