Heidelberg 2015 – wissenschaftliches Programm
MS 13.2: Vortrag
Donnerstag, 26. März 2015, 17:30–17:45, PH/HS2
Supernova-Produced 26Al and 60Fe in Deep-Sea Sediments — •Jenny Feige1, Anton Wallner2, L. Keith Fifield2, Silke Merchel3, Georg Rugel3, Peter Steier1, Steve Tims2, Stephan R. Winkler1, and Robin Golser1 — 1University of Vienna, Austria — 2ANU Canberra, Australia — 3HZDR, Germany
Massive stars, which end their lives in a supernova (SN) explosion, eject freshly produced nuclides into the surrounding interstellar medium. Among them long-lived radionuclides, that can be deposited into terrestrial archives, if such an event occurs close to the Solar System.
About 100 samples of four deep-sea sediment cores originating from the Indian Ocean were analyzed for their content in the isotopes 26Al and 60Fe for the time range of 2-3 Myr. These nuclides are produced in SNe and the time range corresponds to an 60Fe enhancement observed in a deep-ocean crust sample (Knie et al., 2004). The method used for analysis is accelerator mass spectrometry (AMS), a very sensitive technique for the detection of long-lived radionuclides.
A clear signal of 60Fe throughout the whole measured time period was observed. This observation is in contrast to a narrow peak if originating from a direct input from a single SN. Further, no 60Fe was detected in much older or younger sediment samples. A concurring SN-signal of 26Al is, however, hidden underneath a dominant terrestrial background from continuous atmospheric and in-situ production. The resulting limits on the ratios of 60Fe/26Al were compared to nucleosynthesis models.