{"id":55986,"date":"2023-12-16T15:49:52","date_gmt":"2023-12-16T15:49:52","guid":{"rendered":"https:\/\/www.africa-press.net\/tchad\/politique\/le-double-visage-de-la-naine-blanche-janus"},"modified":"2023-12-16T16:04:52","modified_gmt":"2023-12-16T16:04:52","slug":"le-double-visage-de-la-naine-blanche-janus","status":"publish","type":"post","link":"https:\/\/www.africa-press.net\/tchad\/toutes-les-actualites\/le-double-visage-de-la-naine-blanche-janus","title":{"rendered":"Le double visage de la naine blanche Janus"},"content":{"rendered":"<p><span style=\"color: #ff6600\"><strong>Africa-Press &#8211; Tchad. <\/strong><\/span>Surprise en flagrant de\u0301lit de transition ! L&rsquo;e\u0301toile Janus, a\u0300 1300 anne\u0301es-lumie\u0300re, tourne sur elle-me\u0302me toutes les quinze minutes et sa luminosite\u0301 varie d&rsquo;un maximum lorsque sa face recouverte d&rsquo;hydroge\u0300ne est pointe\u0301e vers la Terre, a\u0300 un minimum lorsqu&rsquo;elle pre\u0301sente l&rsquo;he\u0301misphe\u0300re oppose\u0301, recouvert d&rsquo;he\u0301lium. Du jamais-vu pour une naine blanche.<\/p>\n<p><b>Une conversion en quelques secondes<\/b><\/p>\n<p>Certaines sont cependant connues pour, en se refroidissant, passer d&rsquo;une phase hydroge\u0300ne a\u0300 une phase he\u0301lium quand ce gaz remonte en surface a\u0300 cause de phe\u0301nome\u0300nes de convection au centre de l&rsquo;e\u0301toile. Mais cette conversion se fait normalement en quelques secondes et cette dichotomie est ine\u0301dite.<\/p>\n<p><b>Des champs magne\u0301tiques asyme\u0301triques ?<\/b><\/p>\n<p>Des champs magne\u0301tiques asyme\u0301triques pourraient jouer un ro\u0302le en empe\u0302chant l&rsquo;he\u0301lium de se me\u0301langer a\u0300 l&rsquo;hydroge\u0300ne du co\u0302te\u0301 de l&rsquo;he\u0301misphe\u0300re ou\u0300 ils sont les plus puissants, ou en influant sur la pression et la densite\u0301 de l&rsquo;atmosphe\u0300re, autorisant le maintien d&rsquo;un oce\u0301an d&rsquo;hydroge\u0300ne. D&rsquo;autres observations sont ne\u0301cessaires pour mieux comprendre cette e\u0301toile.<\/p>\n<p><strong>Pour plus d&rsquo;informations et d&rsquo;analyses sur la <a href=\"https:\/\/www.africa-press.net\/tchad\">Tchad<\/a>, suivez <a href=\"https:\/\/www.africa-press.net\/\">Africa-Press<\/a><\/strong><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Africa-Press &#8211; Tchad. Surprise en flagrant de\u0301lit de transition ! L&rsquo;e\u0301toile Janus, a\u0300 1300 anne\u0301es-lumie\u0300re, tourne sur elle-me\u0302me toutes les quinze minutes et sa luminosite\u0301 varie d&rsquo;un maximum lorsque sa face recouverte d&rsquo;hydroge\u0300ne est pointe\u0301e vers la Terre, a\u0300 un minimum lorsqu&rsquo;elle pre\u0301sente l&rsquo;he\u0301misphe\u0300re oppose\u0301, recouvert d&rsquo;he\u0301lium. Du jamais-vu pour une naine blanche. Une conversion [&hellip;]<\/p>\n","protected":false},"author":82,"featured_media":55985,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[22,10],"tags":[37,292,29],"class_list":["post-55986","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-divers","category-toutes-les-actualites","tag-africa-press","tag-africa-press-tchad","tag-tchad"],"yoast_head":"<!-- This site is optimized with the Yoast SEO Premium plugin v26.1 (Yoast SEO v27.0) - https:\/\/yoast.com\/product\/yoast-seo-premium-wordpress\/ -->\n<title>Le double visage de la naine blanche Janus - tchad<\/title>\n<meta name=\"description\" content=\"Surprise en flagrant de\u0301lit de transition ! 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