<\/div><\/div>Individual particles from comet 81P\/Wild 2 collected by NASA\u2019s Stardust mission vary in size from small sub-\u03bcm fragments found in the walls of the aerogel tracks, to large fragments up to tens of \u03bcm in size found towards the termini of tracks. The comet, in an orbit beyond Neptune since its formation, retains an intact a record of early-Solar-System processes that was compromised in asteroidal samples by heating and aqueous alteration. We measured the O isotopic composition of seven Stardust fragments larger than \u223c2 \u03bcm extracted from five different Stardust aerogel tracks, and 63 particles smaller than \u223c2 \u03bc m from the wall of a Stardust track. The larger particles show a relatively narrow range of O isotopic compositions that is consistent with 16O16O-poor phases commonly seen in meteorites. Many of the larger Stardust fragments studied so far have chondrule-like mineralogy which is consistent with formation in the inner Solar System. The fine-grained material shows a very broad range of O isotopic compositions (-70-70\u2030< \u039417O\u039417O<+60<+60\u2030) suggesting that Wild 2 fines are either primitive outer-nebula dust or a very diverse sampling of inner Solar System compositional reservoirs that accreted along with a large number of inner-Solar-System rocks to form comet Wild 2.[\/su_quote]\n","protected":false},"excerpt":{"rendered":"
Ryan C. Ogliore, Kazuhide Nagashima, Gary R. Huss, Andrew J. Westphal, Zack Gainsforth, Anna L. Butterworth Geochimica et Cosmochimica Acta In Press, Accepted Manuscript, Available online 24 April 2015 doi:10.1016\/j.gca.2015.04.028 LINK Individual particles from comet…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[179,65],"tags":[1329,1870,1330],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/4470"}],"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=4470"}],"version-history":[{"count":2,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/4470\/revisions"}],"predecessor-version":[{"id":4472,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/4470\/revisions\/4472"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=4470"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=4470"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=4470"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}