{"id":26119,"date":"2021-02-10T21:39:49","date_gmt":"2021-02-10T20:39:49","guid":{"rendered":"https:\/\/karmaka.de\/?p=26119"},"modified":"2021-02-10T22:16:22","modified_gmt":"2021-02-10T21:16:22","slug":"the-micrometeorite-flux-at-dome-c-antarctica-monitoring-the-accretion-of-extraterrestrial-dust-on-earth","status":"publish","type":"post","link":"https:\/\/karmaka.de\/?p=26119","title":{"rendered":"The micrometeorite flux at Dome C (Antarctica), monitoring the accretion of extraterrestrial dust on Earth<span class=\"badge-status\" style=\"background:#787878\">OPEN ACCESS<\/span>&nbsp;"},"content":{"rendered":"\n<p>J. Rojas, J. Duprat, C. Engrand, E. Dartois, L. Delauche, M. Godard, M. Gounelle, J.D. Carrillo-S\u00e1nchez, P. Pokorn\u00fd, J.M.C. Plane<\/p>\n\n\n\n<p>Earth and Planetary Science Letters<br>Volume 560, 15 April 2021, 116794<\/p>\n\n\n\n<p><a rel=\"noreferrer noopener\" href=\"https:\/\/www.sciencedirect.com\/science\/article\/pii\/S0012821X21000534\" target=\"_blank\"><strong>LINK (OPEN ACCESS)<\/strong><\/a><\/p>\n\n\n\n<p>&#8220;Highlights<\/p>\n\n\n\n<p>\u2022 Snow from central Antarctica offers unique advantages for cosmic dust collection.<br>\u2022 Flux measurements with accurate control on the exposure parameter were performed.<br>\u2022 The micrometeorites size distributions are measured down to 30 \u03bcm.<br>\u2022 New constraints on the annual accretion of interplanetary dust by Earth inferred.<br>\u2022 Melted\/un-melted particles proportion indicates the origin of cosmic dust at 1 AU.&#8221;<\/p>\n\n\n\n<p class=\"justify-text\">&#8220;The annual flux of extraterrestrial material on Earth is largely dominated by sub-millimetre particles. The mass distribution and absolute value of this cosmic dust flux at the Earth&#8217;s surface is however still uncertain due to the difficulty in monitoring both the collection efficiency and the exposure parameter (i.e. the area-time product in m2.yr). In this paper, we present results from micrometeorite collections originating from the vicinity of the CONCORDIA Station located at Dome C (Antarctica), where we performed several independent melts of large volumes of ultra-clean snow. The regular precipitation rate and the exceptional cleanliness of the snow from central Antarctica allow a unique control on both the exposure parameter and the collection efficiency. A total of 1280 unmelted micrometeorites (uMMs) and 808 cosmic spherules (CSs) with diameters ranging from 30 to 350 \u03bcm were identified. Within that size range, we measured mass fluxes of 3.0 \u03bcg.m\u22122.yr\u22121 for uMMs and 5.6 \u03bcg.m\u22122.yr\u22121 for CSs. Extrapolated to the global flux of particles in the 12-700 \u03bcm diameter range, the mass flux of dust at Earth&#8217;s surface is 5,200 \u00b1 1500\/1200 tons.yr\u22121 (1,600 \u00b1 500 and 3,600 \u00b1 1000\/700 tons.yr\u22121 of uMMs and CSs, respectively). We indicate the statistical uncertainties expected for collections with exposure parameters in the range of 0.1 up to 105 m2.yr. In addition, we estimated the flux of altered and unaltered carbon carried by heated and un-heated particles at Earth&#8217;s surface. The mass distributions of CSs and uMMs larger than 100 \u03bcm are fairly well reproduced by the CABMOD-ZoDy model that includes melting and evaporation during atmospheric entry of the interplanetary dust flux. These numerical simulations suggest that most of the uMMs and CSs originate from Jupiter family comets and a minor part from the main asteroid belt. The total dust mass input before atmospheric entry is estimated at 15,000 tons.yr\u22121. The existing discrepancy between the flux data and the model for uMMs below 100 \u03bcm suggests that small fragile uMMs may evade present day collections, and\/or that the amount of small interplanetary particles at 1 AU may be smaller than expected.&#8221;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>J. Rojas, J. Duprat, C. Engrand, E. Dartois, L. Delauche, M. Godard, M. Gounelle, J.D. Carrillo-S\u00e1nchez, P. Pokorn\u00fd, J.M.C. Plane Earth and Planetary Science LettersVolume 560, 15 April 2021, 116794 LINK (OPEN ACCESS) &#8220;Highlights \u2022&#8230;<\/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":[4382,5131,4634,327],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/26119"}],"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=26119"}],"version-history":[{"count":4,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/26119\/revisions"}],"predecessor-version":[{"id":26126,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/26119\/revisions\/26126"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=26119"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=26119"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=26119"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}