{"id":13221,"date":"2017-07-04T08:53:07","date_gmt":"2017-07-04T06:53:07","guid":{"rendered":"http:\/\/karmaka.de\/?p=13221"},"modified":"2017-07-22T20:51:04","modified_gmt":"2017-07-22T18:51:04","slug":"j-type-carbon-stars-a-dominant-source-of-14n-rich-presolar-sic-grains-of-type-ab","status":"publish","type":"post","link":"https:\/\/karmaka.de\/?p=13221","title":{"rendered":"J-type carbon stars: A dominant source of 14N-rich presolar SiC grains of type AB<span class=\"badge-status\" style=\"background:#787878\">OPEN ACCESS<\/span>&nbsp;"},"content":{"rendered":"<p>Nan Liu, Thomas Stephan, Patrick Boehnke, Larry R. Nittler, Conel M. O&#8217;D. Alexander, Jianhua Wang, Andrew M. Davis, Reto Trappitsch, Michael J. Pellin<\/p>\n<p>The Astrophysical Journal Letters<\/p>\n<p><a href=\"http:\/\/arxiv.org\/pdf\/1707.00084\" target=\"_blank\"><strong>PDF (OPEN ACCESS)<\/strong><\/a><\/p>\n<p><strong>updated: 22 July 2017<\/strong><br \/>\n<a href=\"http:\/\/iopscience.iop.org\/article\/10.3847\/2041-8213\/aa7d4c\" target=\"_blank\"><strong>LINK<\/strong><\/a> <\/p>\n<p>&#8220;We report Mo isotopic data of 27 new presolar SiC grains, including 12 14N-rich AB (14N\/15N>440, AB2) and 15 mainstream (MS) grains, and their correlated Sr and Ba isotope ratios when available. Direct comparison of the data for the MS grains, which came from low-mass asymptotic giant branch (AGB) stars with large s-process isotope enhancements, with the AB2 grain data demonstrates that AB2 grains show near-solar isotopic compositions and lack s-process enhancements. The near-normal Sr, Mo, and Ba isotopic compositions of AB2 grains clearly exclude born-again AGB stars, where the intermediate neutron-capture process (i-process) takes place, as their stellar source. On the other hand, low-mass CO novae, and early R- and J-type carbon stars show 13C and 14N excesses but no s-process enhancements and are thus potential stellar sources of AB2 grains. Since both early R-type carbon stars and CO novae are rare objects, the abundant J-type carbon stars (10-15% of all carbon stars) are thus likely to be a dominant source of AB2 grains.&#8221;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Nan Liu, Thomas Stephan, Patrick Boehnke, Larry R. Nittler, Conel M. O&#8217;D. Alexander, Jianhua Wang, Andrew M. Davis, Reto Trappitsch, Michael J. Pellin The Astrophysical Journal Letters PDF (OPEN ACCESS) updated: 22 July 2017 LINK&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[9,18,76],"tags":[4021,4022,107,125,3291,1853,539],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/13221"}],"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=13221"}],"version-history":[{"count":2,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/13221\/revisions"}],"predecessor-version":[{"id":13377,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/13221\/revisions\/13377"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=13221"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=13221"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=13221"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}