{"id":3890,"date":"2015-02-20T07:41:27","date_gmt":"2015-02-20T06:41:27","guid":{"rendered":"http:\/\/karmaka.de\/?p=3890"},"modified":"2015-02-20T07:44:07","modified_gmt":"2015-02-20T06:44:07","slug":"low-60fe-abundance-in-semarkona-and-sahara-99555","status":"publish","type":"post","link":"https:\/\/karmaka.de\/?p=3890","title":{"rendered":"Low 60Fe abundance in Semarkona and Sahara 99555"},"content":{"rendered":"<p>Haolan Tang, Nicolas Dauphas<\/p>\n<p>The Astrophysical Journal, in press.<br \/>\narXiv:1502.05611<\/p>\n<p><a href=\"http:\/\/arxiv.org\/pdf\/1502.05611\" target=\"_blank\"><strong>PDF LINK (full text)<\/strong><\/a><\/p>\n<p><a href=\"http:\/\/arxiv.org\/abs\/1502.05611\" target=\"_blank\"><strong>LINK<\/strong><\/a><\/p>\n<div class=\"su-quote su-quote-style-default\"><div class=\"su-quote-inner su-u-clearfix su-u-trim\">Iron-60 (t1\/2=2.62 Myr) is a short-lived nuclide that can help constrain the astrophysical context of solar system formation and date early solar system events. A high abundance of 60Fe (60Fe\/56Fe= 4&#215;10-7) was reported by in situ techniques in some chondrules from the LL3.00 Semarkona meteorite, which was taken as evidence that a supernova exploded in the vicinity of the birthplace of the Sun. However, our previous MC-ICPMS measurements of a wide range of meteoritic materials, including chondrules, showed that 60Fe was present in the early solar system at a much lower level (60Fe\/56Fe=10-8). The reason for the discrepancy is unknown but only two Semarkona chondrules were measured by MC-ICPMS and these had Fe\/Ni ratios below ~2x chondritic. Here, we show that the initial 60Fe\/56Fe ratio in Semarkona chondrules with Fe\/Ni ratios up to ~24x chondritic is 5.4&#215;10-9. We also establish the initial 60Fe\/56Fe ratio at the time of crystallization of the Sahara 99555 angrite, a chronological anchor, to be 1.97&#215;10-9. These results demonstrate that the initial abundance of 60Fe at solar system birth was low, corresponding to an initial 60Fe\/56Fe ratio of 1.01&#215;10-8. <\/div><\/div>\n","protected":false},"excerpt":{"rendered":"<p>Haolan Tang, Nicolas Dauphas The Astrophysical Journal, in press. arXiv:1502.05611 PDF LINK (full text) LINK<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[72,68,71],"tags":[399,449,1825,1816,1013,158],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/3890"}],"collection":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=3890"}],"version-history":[{"count":1,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/3890\/revisions"}],"predecessor-version":[{"id":3891,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/3890\/revisions\/3891"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=3890"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=3890"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=3890"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}