{"id":1943,"date":"2022-07-04T08:03:58","date_gmt":"2022-07-04T07:03:58","guid":{"rendered":"https:\/\/pepsi.aip.de\/?p=1943"},"modified":"2022-07-04T08:07:40","modified_gmt":"2022-07-04T07:07:40","slug":"the-origin-of-weakened-magnetic-braking-in-old-solar-analogs%ef%bf%bc","status":"publish","type":"post","link":"https:\/\/pepsi.aip.de\/?p=1943","title":{"rendered":"The Origin of Weakened Magnetic Braking in Old Solar Analogs"},"content":{"rendered":"\n<p>The rotation rates of main-sequence stars slow over time as they gradually lose angular momentum to their magnetized stellar winds. The rate of angular momentum loss depends on the strength and morphology of the magnetic field, the mass-loss rate, and the stellar rotation period, mass, and radius. Previous observations suggested a shift in magnetic morphology between two F-type stars with similar rotation rates but very different ages (88 Leo and \u03c1 CrB). In this Letter, we identify a comparable transition in an evolutionary sequence of solar analogs with ages between 2\u20137 Gyr. We present new spectropolarimetry of 18 Sco and 16 Cyg A &amp; B from the Large Binocular Telescope, and we reanalyze previously published Zeeman Doppler images of HD 76151 and 18 Sco, providing additional constraints on the nature and timing of this transition.<\/p>\n<figure id=\"attachment_1942\" aria-describedby=\"caption-attachment-1942\" style=\"width: 1375px\" class=\"wp-caption alignnone\"><a href=\"https:\/\/pepsi.aip.de\/wp-content\/uploads\/2022\/07\/F1_2206.08540.png\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-1942\" src=\"https:\/\/pepsi.aip.de\/wp-content\/uploads\/2022\/07\/F1_2206.08540.png\" alt=\"\" width=\"1375\" height=\"790\" srcset=\"https:\/\/pepsi.aip.de\/wp-content\/uploads\/2022\/07\/F1_2206.08540.png 1375w, https:\/\/pepsi.aip.de\/wp-content\/uploads\/2022\/07\/F1_2206.08540-300x172.png 300w, https:\/\/pepsi.aip.de\/wp-content\/uploads\/2022\/07\/F1_2206.08540-1024x588.png 1024w, https:\/\/pepsi.aip.de\/wp-content\/uploads\/2022\/07\/F1_2206.08540-768x441.png 768w\" sizes=\"auto, (max-width: 1375px) 100vw, 1375px\" \/><\/a><figcaption id=\"caption-attachment-1942\" class=\"wp-caption-text\">Stokes V circular polarization profiles for 18 Sco (left) and 16 Cyg A &amp; B (right) from LBT PEPSI observations in 2021 May. Mean profiles are shown as black lines, while uncertainties are indicated with gray shaded areas. Colored lines show axisymmetric model profiles assuming dipole (blue), quadrupole (red), or octupole (magenta) geometry with fixed inclination.<\/figcaption><\/figure>\n\n\n\n<p>Read more: <a href=\"https:\/\/ui.adsabs.harvard.edu\/abs\/2022ApJ...933L..17M\/abstract\">Metcalfe et al. 2022, ApJ Letter, 933, 17<\/a>; arXiv <a href=\"https:\/\/ui.adsabs.harvard.edu\/abs\/2022arXiv220608540M\/abstract\">2206.08540<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>The rotation rates of main-sequence stars slow over time as they gradually lose angular momentum to their magnetized stellar winds. The rate of angular momentum loss depends on the strength and morphology of the magnetic field, the mass-loss rate, and the stellar rotation period, mass, and radius. Previous observations suggested a shift in magnetic morphology &hellip; <a href=\"https:\/\/pepsi.aip.de\/?p=1943\" class=\"more-link\">Continue reading <span class=\"screen-reader-text\">The Origin of Weakened Magnetic Braking in Old Solar Analogs<\/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-1943","post","type-post","status-publish","format-standard","hentry","category-publications"],"_links":{"self":[{"href":"https:\/\/pepsi.aip.de\/index.php?rest_route=\/wp\/v2\/posts\/1943","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=1943"}],"version-history":[{"count":4,"href":"https:\/\/pepsi.aip.de\/index.php?rest_route=\/wp\/v2\/posts\/1943\/revisions"}],"predecessor-version":[{"id":1947,"href":"https:\/\/pepsi.aip.de\/index.php?rest_route=\/wp\/v2\/posts\/1943\/revisions\/1947"}],"wp:attachment":[{"href":"https:\/\/pepsi.aip.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1943"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/pepsi.aip.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1943"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/pepsi.aip.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1943"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}