{"id":31127,"date":"2022-08-13T16:21:41","date_gmt":"2022-08-13T14:21:41","guid":{"rendered":"https:\/\/karmaka.de\/?p=31127"},"modified":"2022-08-13T16:22:07","modified_gmt":"2022-08-13T14:22:07","slug":"presolar-stardust-in-asteroid-ryugu","status":"publish","type":"post","link":"https:\/\/karmaka.de\/?p=31127","title":{"rendered":"Presolar Stardust in Asteroid Ryugu<span class=\"badge-status\" style=\"background:#787878\">OPEN ACCESS<\/span>&nbsp;"},"content":{"rendered":"\n<p>Jens Barosch, Larry R. Nittler, Jianhua Wang, Conel M. O&#8217;D. Alexander, Bradley T. De Gregorio, C\u00e9cile Engrand, Yoko Kebukawa, Kazuhide Nagashima, Rhonda M. Stroud, Hikaru Yabuta et all<\/p>\n\n\n\n<p>The Astrophysical Journal Letters, Volume 935, Number 1<br>Published: 9 August 2022<\/p>\n\n\n\n<p><a href=\"https:\/\/iopscience.iop.org\/article\/10.3847\/2041-8213\/ac83bd\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>LINK (OPEN ACCESS)<\/strong><\/a><br><a href=\"https:\/\/iopscience.iop.org\/article\/10.3847\/2041-8213\/ac83bd\/pdf\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>PDF (OPEN ACCESS)<\/strong><\/a><\/p>\n\n\n\n<p class=\"justify-text\">&#8220;We have conducted a NanoSIMS-based search for presolar material in samples recently returned from C-type asteroid Ryugu as part of JAXA&#8217;s Hayabusa2 mission. We report the detection of all major presolar grain types with O- and C-anomalous isotopic compositions typically identified in carbonaceous chondrite meteorites: 1 silicate, 1 oxide, 1 O-anomalous supernova grain of ambiguous phase, 38 SiC, and 16 carbonaceous grains. At least two of the carbonaceous grains are presolar graphites, whereas several grains with moderate C isotopic anomalies are probably organics. The presolar silicate was located in a clast with a less altered lithology than the typical extensively aqueously altered Ryugu matrix. The matrix-normalized presolar grain abundances in Ryugu are 4.8<em>-2.6\/+4.7 ppm for O-anomalous grains, 25<\/em>-5\/+6 ppm for SiC grains, and 11<em>-3\/+5 ppm for carbonaceous grains. Ryugu is isotopically and petrologically similar to carbonaceous Ivuna-type (CI) chondrites. To compare the in situ presolar grain abundances of Ryugu with CI chondrites, we also mapped Ivuna and Orgueil samples and found a total of 15 SiC grains and 6 carbonaceous grains. No O-anomalous grains were detected. The matrix-normalized presolar grain abundances in the CI chondrites are similar to those in Ryugu: 23<\/em>-6\/+7 ppm SiC and 9.0-3.6\/+5.4 ppm carbonaceous grains. Thus, our results provide further evidence in support of the Ryugu\u2013CI connection. They also reveal intriguing hints of small-scale heterogeneities in the Ryugu samples, such as locally distinct degrees of alteration that allowed the preservation of delicate presolar material.&#8221;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Jens Barosch, Larry R. Nittler, Jianhua Wang, Conel M. O&#8217;D. Alexander, Bradley T. De Gregorio, C\u00e9cile Engrand, Yoko Kebukawa, Kazuhide Nagashima, Rhonda M. Stroud, Hikaru Yabuta et all The Astrophysical Journal Letters, Volume 935, Number&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[77,2243,76,181,1184],"tags":[3872,1854,1771,734,270],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/31127"}],"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=31127"}],"version-history":[{"count":2,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/31127\/revisions"}],"predecessor-version":[{"id":31129,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/31127\/revisions\/31129"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=31127"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=31127"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=31127"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}