{"id":33990,"date":"2023-07-18T15:12:43","date_gmt":"2023-07-18T13:12:43","guid":{"rendered":"https:\/\/karmaka.de\/?p=33990"},"modified":"2023-08-12T00:55:40","modified_gmt":"2023-08-11T22:55:40","slug":"origin-of-low-26al-27al-corundum-hibonite-inclusions-in-meteorites","status":"publish","type":"post","link":"https:\/\/karmaka.de\/?p=33990","title":{"rendered":"Origin of Low-26Al\/27Al Corundum\/Hibonite Inclusions in Meteorites<span class=\"badge-status\" style=\"background:#787878\">OPEN ACCESS<\/span>&nbsp;"},"content":{"rendered":"\n<p>Steven J. Desch, Emilie T. Dunham, Ashley K. Herbst, Cayman T. Unterborn, Thomas G. Sharp, Maitrayee Bose, Prajkta Mane, Curtis D. Williams<\/p>\n\n\n\n<p>Accepted to The Astrophysical Journal<\/p>\n\n\n\n<p><a href=\"https:\/\/arxiv.org\/pdf\/2307.07750.pdf\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>PDF (OPEN ACCESS)<\/strong><\/a><\/p>\n\n\n\n<p>Update (11 August 2023): The Astrophysical Journal, Volume 953, Number 2<\/p>\n\n\n\n<p><a href=\"https:\/\/iopscience.iop.org\/article\/10.3847\/1538-4357\/acdeed\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>LINK (OPEN ACCESS)<\/strong><\/a><br><a href=\"https:\/\/iopscience.iop.org\/article\/10.3847\/1538-4357\/acdeed\/pdf\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>PDF (OPEN ACCESS)<\/strong><\/a><\/p>\n\n\n\n<p class=\"justify-text\">&#8220;Most meteoritic calcium-rich, aluminum-rich inclusions (CAIs) formed from a reservoir with 26Al\/27Al \u2248 5 \u00d7 10\u22125, but some record lower (26Al\/27Al)0, demanding they sampled a reservoir without live 26Al. This has been interpreted as evidence for \u201clate injection\u201d of supernova material into our protoplanetary disk. We instead interpret the heterogeneity as chemical, demonstrating that these inclusions are strongly associated with the refractory phases corundum or hibonite. We name them \u201cLow-26Al\/27Al Corundum\/Hibonite Inclusions\u201d (LAACHIs). We present a detailed astrophysical model for LAACHI formation in which they derive their Al from presolar corundum, spinel or hibonite grains 0.5 \u2212 2 \u03bcm in size with no live 26Al; live 26Al is carried on smaller (&lt;50 nm) presolar chromium spinel grains from recent nearby Wolf-Rayet stars or supernovae. In hot (\u2248 1350-1425 K) regions of the disk these grains, and perovskite grains, would be the only survivors. These negatively charged grains would grow to sizes 1 \u2212 103 \u03bcm, even incorporating positively charged perovskite grains, but not the small, negatively charged 26Al-bearing grains. Chemical and isotopic fractionations due to grain charging was a significant process in hot regions of the disk. Our model explains the sizes, compositions, oxygen isotopic signatures, and the large, correlated 48Ca and 50Ti anomalies (if carried by presolar perovskite) of LAACHIs, and especially how they incorporated no 26Al in a solar nebula with uniform, canonical 26Al\/27Al. A late injection of supernova material is obviated, although formation of the Sun in a high-mass star-forming region is demanded.&#8221;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Steven J. Desch, Emilie T. Dunham, Ashley K. Herbst, Cayman T. Unterborn, Thomas G. Sharp, Maitrayee Bose, Prajkta Mane, Curtis D. Williams Accepted to The Astrophysical Journal PDF (OPEN ACCESS) Update (11 August 2023): The&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[66,72,65],"tags":[238,448,1846,4628,2769,4037,6530,1845,1015],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/33990"}],"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=33990"}],"version-history":[{"count":2,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/33990\/revisions"}],"predecessor-version":[{"id":34073,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/33990\/revisions\/34073"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=33990"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=33990"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=33990"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}