LINK<\/strong><\/a><\/p>\n“Comet 81P\/Wild 2 dust, the first comet sample of known provenance, was widely expected to resemble anhydrous chondritic porous (CP) interplanetary dust particles (IDPs). GEMS, distinctly characteristic of CP IDPs, have yet to be unambiguously identified in the Stardust mission samples despite claims of likely candidates. One such candidate is Stardust impact track 57 \u201cFebo\u201d in aerogel, which contains fine\u2010grained objects texturally and compositionally similar to GEMS. Their position adjacent the terminal particle suggests that they may be indigenous, fine\u2010grained, cometary material, like that in CP IDPs, shielded by the terminal particle from damage during deceleration from hypervelocity. Dark\u2010field imaging and multidetector energy\u2010dispersive X\u2010ray mapping were used to compare GEMS\u2010like\u2010objects in the Febo terminal particle with GEMS in an anhydrous, chondritic IDP. GEMS in the IDP are within 3\u00d7 CI (solar) abundances for major and minor elements. In the Febo GEMS\u2010like objects, Mg and Ca are systematically and strongly depleted relative to CI; S and Fe are somewhat enriched; and Au, a known aerogel contaminant, is present, consistent with ablation, melting, abrasion, and mixing of the SiOx aerogel with crystalline Fe\u2010sulfide and minor enstatite, high\u2010Ni sulfide, and augite identified by elemental mapping in the terminal particle. Thus, GEMS\u2010like objects in \u201ccaches\u201d of fine\u2010grained debris abutting terminal particles are most likely deceleration debris packed in place during particle transit through the aerogel. “<\/p>\n","protected":false},"excerpt":{"rendered":"
Hope A. Ishii Meteoritics & Planetary Science First published: 5 August 2018 LINK “Comet 81P\/Wild 2 dust, the first comet sample of known provenance, was widely expected to resemble anhydrous chondritic porous (CP) interplanetary dust…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[179],"tags":[710,1870,714,1083],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/16066"}],"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=16066"}],"version-history":[{"count":1,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/16066\/revisions"}],"predecessor-version":[{"id":16067,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/16066\/revisions\/16067"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=16066"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=16066"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=16066"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}