{"id":9404,"date":"2016-07-12T06:53:55","date_gmt":"2016-07-12T04:53:55","guid":{"rendered":"http:\/\/karmaka.de\/?p=9404"},"modified":"2016-07-12T06:53:55","modified_gmt":"2016-07-12T04:53:55","slug":"boron-abundances-and-isotopic-ratios-of-olivine-grains-on-itokawa-returned-by-the-hayabusa-spacecraft","status":"publish","type":"post","link":"https:\/\/karmaka.de\/?p=9404","title":{"rendered":"Boron abundances and isotopic ratios of olivine grains on Itokawa returned by the Hayabusa spacecraft."},"content":{"rendered":"<p>Fujiya, W., Hoppe, P. and Ott, U.<\/p>\n<p>Meteoritics &#038; Planetary Science. doi: 10.1111\/maps.12686<\/p>\n<p><a href=\"http:\/\/onlinelibrary.wiley.com\/doi\/10.1111\/maps.12686\/abstract\" target=\"_blank\"><strong>LINK<\/strong><\/a><\/p>\n<p>&#8220;We report the B abundances and isotopic ratios of two olivine grains from the S-type asteroid Itokawa sampled by the Hayabusa spacecraft. Olivine grains from the Dar al Gani (DaG) 989 LL6 chondrite were used as a reference. Since we analyzed polished thin sections in both cases, we expect the contribution from the solar wind B (rich in 10B) to be minimal because the solar wind was implanted only within very thin layers of the grain surface. The Itokawa and DaG 989 olivine grains have homogeneous B abundances (~400 ppb) and 11B\/10B ratios compatible with the terrestrial standard and bulk chondrites. The observed homogeneous B abundances and isotopic ratios of the Itokawa olivine grains are likely the result of thermal metamorphism which occurred in the parent asteroid of Itokawa, which had a similar composition as LL chondrites. The chondritic B isotopic ratios of the Itokawa samples suggest that they contain little cosmogenic B (from cosmic-ray spallation reactions) rich in 10B. This observation is consistent with the short cosmic-ray exposure ages of Itokawa samples inferred from the small concentrations of cosmogenic 21Ne. If other Itokawa samples have little cosmogenic B as well, the enrichment in 10B found previously on the surface of another Itokawa particle (as opposed to the bulk grain study here) may be attributed to implanted solar wind B.&#8221;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Fujiya, W., Hoppe, P. and Ott, U. Meteoritics &#038; Planetary Science. doi: 10.1111\/maps.12686 LINK &#8220;We report the B abundances and isotopic ratios of two olivine grains from the S-type asteroid Itokawa sampled by the Hayabusa&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[77,182,7,3035,181],"tags":[3036,1871,792,3037],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/9404"}],"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=9404"}],"version-history":[{"count":1,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/9404\/revisions"}],"predecessor-version":[{"id":9405,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/9404\/revisions\/9405"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=9404"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=9404"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=9404"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}