{"id":19883,"date":"2019-06-27T08:44:41","date_gmt":"2019-06-27T06:44:41","guid":{"rendered":"http:\/\/karmaka.de\/?p=19883"},"modified":"2019-08-10T01:20:45","modified_gmt":"2019-08-09T23:20:45","slug":"presolar-silicon-carbide-grains-of-types-y-and-z-their-molybdenum-isotopic-compositions-and-stellar-origins","status":"publish","type":"post","link":"https:\/\/karmaka.de\/?p=19883","title":{"rendered":"Presolar Silicon Carbide Grains of Types Y and Z: Their Molybdenum Isotopic Compositions and Stellar Origins<span class=\"badge-status\" style=\"background:#787878\">OPEN ACCESS<\/span>&nbsp;"},"content":{"rendered":"\n<p>Nan Liu, Thomas Stephan, Sergio Cristallo, Roberto Gallino, Patrick Boehnke, Larry R. Nittler, Conel M. O.&#8217;D. Alexander, Andrew M. Davis, Reto Trappitsch, Michael J. Pellin, Iris Dillmann<\/p>\n\n\n\n<p>The Astrophysical Journal (Accepted)<\/p>\n\n\n\n<p><a href=\"https:\/\/arxiv.org\/pdf\/1906.10776\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>PDF (OPEN ACCESS)<\/strong><\/a><\/p>\n\n\n\n<p>Update (9 August 2019): <a rel=\"noreferrer noopener\" href=\"https:\/\/iopscience.iop.org\/article\/10.3847\/1538-4357\/ab2d27\" target=\"_blank\"><strong>LINK<\/strong><\/a><\/p>\n\n\n\n<p class=\"justify-text\">&#8220;We report Mo isotopic compositions of 37 presolar SiC grains of types Y (19) and Z (18), rare types commonly  argued  to  have  formed  in  lower-than-solar  metallicity  asymptotic  giant branch  (AGB)  stars. Direct  comparison  of the Y  and  Z  grain  data  with  data  for mainstream grains from  AGB  stars of  close-to-solar  metallicity demonstrates that the  three types of  grains have indistinguishable Mo isotopic compositions. We show that the Mo isotope data can be used to constrain the maximum stellar  temperatures (TMAX) during  thermal  pulses  in AGB stars. Comparison of FRUITY Torino AGB nucleosynthesis model calculations with the grain data for Mo isotopes points to an origin from low-mass (~1.5\u20133M!) rather than intermediate-mass (&gt;3\u2013~9M!) AGB stars. Because  of  the  low  efficiency  of 22Ne(\u03b1,n)25Mg at the  low TMAX values attained in low-mass AGB stars, model calculations cannot explain the large 30Si excesses of Z grains as arising from neutron capture, so these excesses remain a puzzle at the moment.&#8221;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Nan Liu, Thomas Stephan, Sergio Cristallo, Roberto Gallino, Patrick Boehnke, Larry R. Nittler, Conel M. O.&#8217;D. Alexander, Andrew M. Davis, Reto Trappitsch, Michael J. Pellin, Iris Dillmann The Astrophysical Journal (Accepted) PDF (OPEN ACCESS) Update&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[9,18,76],"tags":[3930,107,1853,539,3647],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/19883"}],"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=19883"}],"version-history":[{"count":2,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/19883\/revisions"}],"predecessor-version":[{"id":20250,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/19883\/revisions\/20250"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=19883"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=19883"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=19883"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}