Berlin 2014 – wissenschaftliches Programm

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MS: Fachverband Massenspektrometrie

MS 7: Fathoming Stellar Evolution (Part 2)

MS 7.4: Vortrag

Mittwoch, 19. März 2014, 17:45–18:00, DO24 1.205

Detecting Supernova Dust on the Earth’s Sea Floor with AMS — •Jenny Feige¹, Anton Wallner², Dieter Breitschwerdt³, L. Keith Fifield², Gunther Korschinek⁴, Silke Merchel⁵, Georg Rugel⁵, Peter Steier¹, Steve Tims², Stephan R. Winkler¹, and Robin Golser¹ — ¹University of Vienna, Austria — ²ANU Canberra, Australia — ³TU Berlin, Germany — ⁴TUM, Germany — ⁵HZDR, Germany

An ⁶⁰Fe anomaly was detected with accelerator mass spectrometry (AMS) - a very sensitive method to measure extremely low isotopic ratios - in a 2 Myr old layer of a ferromanganese crust (Knie et al., 2004). This signal is assumed to be of supernova origin and might be linked to the observation of our solar system being located in a region of thin, hot interstellar medium. This region, called the Local Bubble, was presumably formed by multiple supernova explosions starting ∼14 Myr ago. Calculations suggest that at least one of these supernovae occured close enough to the solar system to leave a detectable ⁶⁰Fe trace on Earth.
New AMS measurements are performed in deep-sea sediments from the Pacific Ocean. An international collaboration of different AMS facilities searches for signatures of the long-lived radionuclides ²⁶Al, ⁵³Mn, and ⁶⁰Fe in a time range from 1.7 to 3.1 Myr. Magnetostratigraphic dating of the samples is confirmed by measurements of the cosmogenic radionuclide ¹⁰Be. All ¹⁰Be and ²⁶Al measurements are finished, ⁵³Mn and ⁶⁰Fe is in progress. First results will be presented and discussed.