{"id":1697,"date":"2021-01-08T07:49:00","date_gmt":"2021-01-08T06:49:00","guid":{"rendered":"https:\/\/pepsi.aip.de\/?p=1697"},"modified":"2022-01-19T08:52:24","modified_gmt":"2022-01-19T07:52:24","slug":"strongly-magnetic-ofp-star-ngc-1624-2","status":"publish","type":"post","link":"https:\/\/pepsi.aip.de\/?p=1697","title":{"rendered":"Strongly magnetic Of?p star NGC 1624-2"},"content":{"rendered":"\n<p>NGC 1624-2 is an O7f?p star with a reported probable polar magnetic field strength \u226520 kG, which is the strongest magnetic field ever measured in an O-type star. We study the variability of the mean longitudinal magnetic field &lt;B<sub>z<\/sub>&gt; and the mean field modulus to obtain constraints on its field geometry. Only one magnetic pole is observable over the rotation cycle. The approximately sinusoidal variation of &lt;B<sub>z<\/sub>&gt; and the ratio of the values of the extrema of indicate that there is an important component of the field that is dipolar. The &lt;B<sub>z<\/sub>&gt; values measured over the rotation cycle are in the range from -0.2 to 4.5 kG, whereas the values for vary between 9 and 12 kG. The &lt;B<sub>z<\/sub>&gt; values obtained using the O III \u03bb7455 emission line are in the range from 0.4 to 2.3 kG and show a variability pattern similar to that detected for the absorption lines. The fact that the phase of the &lt;B<sub>z<\/sub>&gt; minimum coincides with the phase of the maximum, indicates that the field structure must significantly depart from a centred dipole. Further, we discuss the nature of the observed variable Stokes V profiles corresponding to a longitudinal field of negative polarity detected in the emission He I lines and present the first magnetohydrodynamical numerical simulations of the gas flow in the magnetosphere of this star.<\/p>\n<figure id=\"attachment_1692\" aria-describedby=\"caption-attachment-1692\" style=\"width: 800px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/pepsi.aip.de\/wp-content\/uploads\/2021\/02\/split.png\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-1692\" src=\"https:\/\/pepsi.aip.de\/wp-content\/uploads\/2021\/02\/split-300x263.png\" alt=\"\" width=\"800\" height=\"700\" srcset=\"https:\/\/pepsi.aip.de\/wp-content\/uploads\/2021\/02\/split-300x263.png 300w, https:\/\/pepsi.aip.de\/wp-content\/uploads\/2021\/02\/split-1024x896.png 1024w, https:\/\/pepsi.aip.de\/wp-content\/uploads\/2021\/02\/split-768x672.png 768w, https:\/\/pepsi.aip.de\/wp-content\/uploads\/2021\/02\/split-1536x1344.png 1536w, https:\/\/pepsi.aip.de\/wp-content\/uploads\/2021\/02\/split-2048x1792.png 2048w\" sizes=\"auto, (max-width: 800px) 100vw, 800px\" \/><\/a><figcaption id=\"caption-attachment-1692\" class=\"wp-caption-text\">The split components of the magnetically resolved line C IV \u03bb5812.<\/figcaption><\/figure>\n<p>Read more: <a href=\"https:\/\/ui.adsabs.harvard.edu\/abs\/2021MNRAS.501.4534J\/abstract\">J\u00e4rvinen et al., 2021, MNRAS, 501, 4534<\/a>, in <a href=\"https:\/\/arxiv.org\/pdf\/2101.00899.pdf\">arXiv<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>NGC 1624-2 is an O7f?p star with a reported probable polar magnetic field strength \u226520 kG, which is the strongest magnetic field ever measured in an O-type star. We study the variability of the mean longitudinal magnetic field &lt;Bz&gt; and the mean field modulus to obtain constraints on its field geometry. Only one magnetic pole &hellip; <a href=\"https:\/\/pepsi.aip.de\/?p=1697\" class=\"more-link\">Continue reading <span class=\"screen-reader-text\">Strongly magnetic Of?p star NGC 1624-2<\/span> <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":5,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[11],"tags":[],"class_list":["post-1697","post","type-post","status-publish","format-standard","hentry","category-publications"],"_links":{"self":[{"href":"https:\/\/pepsi.aip.de\/index.php?rest_route=\/wp\/v2\/posts\/1697","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pepsi.aip.de\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/pepsi.aip.de\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/pepsi.aip.de\/index.php?rest_route=\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/pepsi.aip.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1697"}],"version-history":[{"count":5,"href":"https:\/\/pepsi.aip.de\/index.php?rest_route=\/wp\/v2\/posts\/1697\/revisions"}],"predecessor-version":[{"id":1897,"href":"https:\/\/pepsi.aip.de\/index.php?rest_route=\/wp\/v2\/posts\/1697\/revisions\/1897"}],"wp:attachment":[{"href":"https:\/\/pepsi.aip.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1697"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/pepsi.aip.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1697"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/pepsi.aip.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1697"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}