{"id":16835,"date":"2018-12-01T07:57:45","date_gmt":"2018-12-01T06:57:45","guid":{"rendered":"http:\/\/karmaka.de\/?p=16835"},"modified":"2018-12-01T07:57:45","modified_gmt":"2018-12-01T06:57:45","slug":"the-atmospheric-entry-of-fine%e2%80%90grained-micrometeorites-the-role-of-volatile-gases-in-heating-and-fragmentation","status":"publish","type":"post","link":"https:\/\/karmaka.de\/?p=16835","title":{"rendered":"The atmospheric entry of fine\u2010grained micrometeorites: The role of volatile gases in heating and fragmentation"},"content":{"rendered":"

M. D. Suttle, M. J. Genge, L. Folco, M. Van Ginneken, Q. Lin, S. S. Russell, J. Najorka<\/p>\n

Meteoritics & Planetary Science
\nFirst Published: 30 November 2018<\/p>\n

LINK<\/strong><\/a><\/p>\n

“The early stages of atmospheric entry are investigated in four large (250\u2013950 \u03bcm) unmelted micrometeorites (three fine\u2010grained and one composite), derived from the Transantarctic Mountain micrometeorite collection. These particles have abundant, interconnected, secondary pore spaces which form branching channels and show evidence of enhanced heating along their channel walls. Additionally, a micrometeorite with a double\u2010walled igneous rim is described, suggesting that some particles undergo volume expansion during entry. This study provides new textural data which links together entry heating processes known to operate inside micrometeoroids, thereby generating a more comprehensive model of their petrographic evolution. Initially, flash heated micrometeorites develop a melt layer on their exterior; this igneous rim migrates inwards. Meanwhile, the particle core is heated by the decomposition of low\u2010temperature phases and by volatile gas release. Where the igneous rim acts as a seal, gas pressures rise, resulting in the formation of interconnected voids and higher particle porosities. Eventually, the igneous rim is breached and gas exchange with the atmosphere occurs. This mechanism replaces inefficient conductive rim\u2010to\u2010core thermal gradients with more efficient particle\u2010wide heating, driven by convective gas flow. Interconnected voids also increase the likelihood of particle fragmentation during entry and, may therefore explain the rarity of large fine\u2010grained micrometeorites among collections.”<\/p>\n","protected":false},"excerpt":{"rendered":"

M. D. Suttle, M. J. Genge, L. Folco, M. Van Ginneken, Q. Lin, S. S. Russell, J. Najorka Meteoritics & Planetary Science First Published: 30 November 2018 LINK “The early stages of atmospheric entry are…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3157],"tags":[],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/16835"}],"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=16835"}],"version-history":[{"count":1,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/16835\/revisions"}],"predecessor-version":[{"id":16836,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/16835\/revisions\/16836"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=16835"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=16835"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=16835"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}