No mention of square planetesimals... http://www.sciencemag.org/cgi/content/abstract/316/5828/1178
Evidence for a Late Supernova Injection of 60Fe into the Protoplanetary Disk Martin Bizzarro,1,2* David Ulfbeck,1 Anne Trinquier,1 Kristine Thrane,1 James N. Connelly,1,3 Bradley S. Meyer4 High-precision 60Fe-60Ni isotope data show that most meteorites originating from differentiated planetesimals that accreted within 1 million years of the solar system's formation have 60Ni/58Ni ratios that are 25 parts per million lower than samples from Earth, Mars, and chondrite parent bodies. This difference indicates that the oldest solar system planetesimals formed in the absence of 60Fe. Evidence for live 60Fe in younger objects suggests that 60Fe was injected into the protoplanetary disk 1 million years after solar system formation, when 26Al was already homogeneously distributed. Decoupling the first appearance of 26Al and 60Fe constrains the environment where the Sun's formation could have taken place, indicating that it occurred in a dense stellar cluster in association with numerous massive stars. 1 Geological Institute, University of Copenhagen, Øster Voldgade 10, DK-1350, Denmark. 2 Geological Museum, University of Copenhagen, Øster Voldgade 5-7, DK-1350, Denmark. 3 Jackson School of Geosciences, University of Texas at Austin, Austin, TX 78712, USA. 4 Department of Physics and Astronomy, Clemson University, Clemson, SC 296340978, USA. * To whom correspondence should be addressed. E-mail: [EMAIL PROTECTED] ______________________________________________ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
