{"id":1194,"date":"2024-12-07T18:54:15","date_gmt":"2024-12-07T17:54:15","guid":{"rendered":"https:\/\/utf.mff.cuni.cz\/~pejcha\/?p=1194"},"modified":"2024-12-07T18:54:15","modified_gmt":"2024-12-07T17:54:15","slug":"journey-to-the-center-of-the-common-envelope-evolution","status":"publish","type":"post","link":"https:\/\/utf.mff.cuni.cz\/~pejcha\/index.php\/2024\/12\/07\/journey-to-the-center-of-the-common-envelope-evolution\/","title":{"rendered":"Journey to the center of the common envelope evolution"},"content":{"rendered":"\n

Is there a contact binary sitting at the center of common envelope? Do we actually need magnetic fields to explain the “jets” seen in planetary nebulae?<\/strong> These are very exciting questions resulting from the Damien Gagnier’s third paper<\/a> written during his postdoc stint in Prague.<\/p>\n\n\n\n

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Differently to his previous works and other literature, Damien used Athena++ adaptive mesh refinement capabilities to setup up to 8 levels of refinement zooming-in on the center of the common envelope, focusing on the dynamics of the central binary.<\/p>\n\n\n\n

First question to address is what is the required resolution in light of the necessary smoothing of gravitational potential? Damien looked at quantities like inspiral timescale or shearing rate showing that perhaps most existing simulations become underresolved at late times.<\/p>\n\n\n\n

Second question is the gas distribution around the binary. The finding is quite surprising: the gas organizes in a nearly hydrostatic corotating structure resembling a contact binary! Based on the analogy, we attempt to discuss what is the ultimate fate of this structure and how it can modify the cores if sufficiently long lived.<\/p>\n\n\n\n

Finally, Damien quite surprisingly found polar “jets” or outflows emanating from the central regions and collimated by the polar funnel evacuated by the centrifugal force in the envelope. The outflows are intermittent, but the absence of magnetic fields in the simulation makes their existence surprising. <\/p>\n","protected":false},"excerpt":{"rendered":"

Is there a contact binary sitting at the center of common envelope? Do we actually need magnetic fields to explain the “jets” seen in planetary nebulae? These are very exciting questions resulting from the Damien Gagnier’s third paper written during his postdoc stint in Prague.<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[1],"tags":[],"_links":{"self":[{"href":"https:\/\/utf.mff.cuni.cz\/~pejcha\/index.php\/wp-json\/wp\/v2\/posts\/1194"}],"collection":[{"href":"https:\/\/utf.mff.cuni.cz\/~pejcha\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/utf.mff.cuni.cz\/~pejcha\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/utf.mff.cuni.cz\/~pejcha\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/utf.mff.cuni.cz\/~pejcha\/index.php\/wp-json\/wp\/v2\/comments?post=1194"}],"version-history":[{"count":1,"href":"https:\/\/utf.mff.cuni.cz\/~pejcha\/index.php\/wp-json\/wp\/v2\/posts\/1194\/revisions"}],"predecessor-version":[{"id":1198,"href":"https:\/\/utf.mff.cuni.cz\/~pejcha\/index.php\/wp-json\/wp\/v2\/posts\/1194\/revisions\/1198"}],"wp:attachment":[{"href":"https:\/\/utf.mff.cuni.cz\/~pejcha\/index.php\/wp-json\/wp\/v2\/media?parent=1194"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/utf.mff.cuni.cz\/~pejcha\/index.php\/wp-json\/wp\/v2\/categories?post=1194"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/utf.mff.cuni.cz\/~pejcha\/index.php\/wp-json\/wp\/v2\/tags?post=1194"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}