Session X8: Geophysical Astronomy

10:45 AM–11:57 AM, Tuesday, April 16, 2013
Room: Governor's Square 10

Sponsoring Unit: DAP
Chair: Adrian Melott, University of Kansas

Abstract ID: BAPS.2013.APR.X8.2

Abstract: X8.00002 : Search for Supernova $^{60}$Fe in the Earth's Fossil Record

10:57 AM–11:09 AM

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Authors:

  Shawn Bishop
    (Technische Universit\"at M\"unchen, James-Franck Strasse, 85748 Garching, Germany)

  Peter Ludwig
    (Technische Universit\"at M\"unchen, James-Franck Strasse, 85748 Garching, Germany)

  Ramon Egli
    (Geomagnetism and Gravimetry, Central Institute for Meteorology and Geodynamics, Hohe Warte 38, 1190 Vienna, Austria)

  Valentina Chernenko
    (Technische Universit\"at M\"unchen, James-Franck Strasse, 85748 Garching, Germany)

  Thomas Frederichs
    (Department of Geosciences, Universit\"at Bremen, Klagenfurter Strasse, 28359 Bremen, Germany)

  Silke Merchel
    (Institute of Ion Beam Physics, Research Center Dresden-Rossendorf, 01314 Dresden, Germany)

  Georg Rugel
    (Institute of Ion Beam Physics, Research Center Dresden-Rossendorf, 01314 Dresden, Germany)

Approximately 2.8 Myr before the present our planet was subjected to the debris of a supernova explosion. The terrestrial proxy for this event was the discovery of live atoms of $^{60}$Fe in a deep-sea ferromanganese crust. The signature for this supernova event should also reside in magnetite (Fe$_3$O$_4$) magnetofossils produced by magnetotactic bacteria extant at the time of the Earth- supernova interaction, provided the bacteria preferentially uptake iron from fine-grained iron oxides and ferric hydroxides. Using empirically derived microfossil concentrations in a deep-sea drill core, we deduce a conservative estimate of the 60Fe fraction as $^{60}$Fe/Fe $= 3.6 \times 10^{-15}$. This value sits comfortably within the sensitivity limit of present accelerator mass spectrometry (AMS) capabilities. This talk will detail the present status of our $^{60}$Fe AMS search in magnetofossils and (possibly) show our initial results.

To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2013.APR.X8.2