{"id":1060,"date":"2007-07-12T13:03:00","date_gmt":"2007-07-12T11:03:00","guid":{"rendered":"https:\/\/kids.esa.int\/scientists_find_an_extrasolar_sauna\/"},"modified":"2026-10-08T00:35:27","modified_gmt":"2026-10-07T22:35:27","slug":"scientists_find_an_extrasolar_sauna","status":"publish","type":"post","link":"https:\/\/kids.esa.int\/fr\/scientists_find_an_extrasolar_sauna\/","title":{"rendered":"Un sauna extrasolaire"},"content":{"rendered":"<div class=\"lede\">\n<p>Un extra-terrestre qui survolerait la Terre ne manquerait pas de remarquer la vaste pr\u00e9sence d'eau \u00e0 la surface de notre plan\u00e8te bleue. De toute fa\u00e7on, la Terre est la seule plan\u00e8te de notre syst\u00e8me solaire \u00e0 \u00eatre recouverte d'eau. Et puisque les plan\u00e8tes humides sont une chose rare, on ne s'\u00e9tonnera pas de l'enthousiasme des scientifiques, face \u00e0 la d\u00e9couverte d'une atmosph\u00e8re riche en eau sur une plan\u00e8te en orbite autour d'une \u00e9toile distante.<\/p>\n<\/div>\n<p>Plus de de 200 exoplan\u00e8tes ont \u00e9t\u00e9 recens\u00e9es, mais rares sont celles qui ont \u00e9t\u00e9 observ\u00e9es ou pour lesquelles nous avons des images. Par bonheur, certaines de ces plan\u00e8tes \"invisibles\" ont pu \u00eatre d\u00e9tect\u00e9es au moment de leur transit ou de leur passage devant leur \u00e9toile. C'est ainsi que la g\u00e9ante gazeuse HD 189733b a \u00e9t\u00e9 d\u00e9couverte en 2005. En effet, cette plan\u00e8te similaire \u00e0 Jupiter, avait provoqu\u00e9 une att\u00e9nuation de l'intensit\u00e9 lumineuse \u00e9mise par son \u00e9toile-m\u00e8re.<\/p>\n<figure class=\"wp-block-image size-natural\" data-width=\"400\" data-credit=\"ESA (C.Carreau)\" data-detail-url=\"https:\/\/www.esa.int\/ESA_Multimedia\/Images\/2007\/07\/Transiting_exoplanet_HD_189733b_in_the_infrared2\" data-licence=\"ESA Standard Licence\" data-licence-url=\"https:\/\/www.esa.int\/ESA_Multimedia\/Terms_and_conditions_of_use_of_images_and_videos_available_on_the_esa_website\"><img decoding=\"async\" loading=\"lazy\" style=\"max-width:100%;height:auto\" src=\"https:\/\/www.esa.int\/var\/esa\/storage\/images\/esa_multimedia\/images\/2007\/07\/transiting_exoplanet_hd_189733b_in_the_infrared2\/17867266-3-eng-GB\/Transiting_exoplanet_HD_189733b_in_the_infrared.jpg\" alt=\"Transiting exoplanet HD 189733b, in the infrared\"><figcaption>L'exoplan\u00e8te en transit HD 189733b, dans l'infrarouge<\/figcaption><\/figure>\n<p>Depuis, HD 189733b a fait l'objet de diverses autres \u00e9tudes par les scientifiques europ\u00e9ens et am\u00e9ricains, qui gr\u00e2ce au t\u00e9lescope spatial Spitzer de la NASA, ont pu mesurer la lumi\u00e8re infrarouge provenant de l'\u00e9toile. Au fur et \u00e0 mesure que la plan\u00e8te traversait le disque stellaire, son atmosph\u00e8re externe a plus obstru\u00e9 une longueur d'onde de lumi\u00e8re que les deux autres longueurs d'onde. La seule explication \u00e0 ce ph\u00e9nom\u00e8ne est la pr\u00e9sence de vapeur d'eau dans l'atmosph\u00e8re de la plan\u00e8te.<\/p>\n<p>Malheureusement, la plan\u00e8te g\u00e9ante n'est pas un monde rocheux, ce qui favoriserait la formation d'oc\u00e9ans. En plus, elle orbite trop pr\u00e8s de son \u00e9toile. Avec une temp\u00e9rature atmosph\u00e9rique d\u00e9passant les 700\u00b0C, l'air est trop chaud pour qu'il y pleuve. HD 189733b est tr\u00e8s certainement inhabit\u00e9e. Ces r\u00e9sultats, toutefois, font \u00e9merger l'espoir de d\u00e9couvrir, dans un futur pas trop lointain, des plan\u00e8tes similaires \u00e0 la Terre.<\/p>","protected":false},"excerpt":{"rendered":"<p>An alien flying past the Earth could hardly fail to notice that our blue planet is largely covered by oceans. However, Earth is the only water-covered world in our Solar [&hellip;]<\/p>\n","protected":false},"author":5,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"esa_banner_image":"https:\/\/www.esa.int\/var\/esa\/storage\/images\/esa_multimedia\/images\/2007\/07\/transiting_exoplanet_hd_189733b2\/17903269-2-eng-GB\/Transiting_exoplanet_HD_189733b.jpg","esa_banner_description":"Transiting exoplanet HD 189733b","esa_banner_credit":"ESA - C.Carreau","esa_banner_licence":"ESA Standard Licence","esa_banner_detail_url":"https:\/\/www.esa.int\/ESA_Multimedia\/Images\/2007\/07\/Transiting_exoplanet_HD_189733b2","esa_external_url":"","esa_external_new_window":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_post_was_ever_published":true},"categories":[14,10,13],"tags":[],"panel":[],"language":[],"age":[],"duration":[],"resource_type":[],"audience":[],"wf_post_folders":[],"class_list":["post-1060","post","type-post","status-publish","format-standard","hentry","category-are-we-alone","category-learn","category-life-in-space"],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/posts\/1060","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/comments?post=1060"}],"version-history":[{"count":5,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/posts\/1060\/revisions"}],"predecessor-version":[{"id":4828,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/posts\/1060\/revisions\/4828"}],"wp:attachment":[{"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/media?parent=1060"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/categories?post=1060"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/tags?post=1060"},{"taxonomy":"panel","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/panel?post=1060"},{"taxonomy":"language","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/language?post=1060"},{"taxonomy":"age","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/age?post=1060"},{"taxonomy":"duration","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/duration?post=1060"},{"taxonomy":"resource_type","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/resource_type?post=1060"},{"taxonomy":"audience","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/audience?post=1060"},{"taxonomy":"wf_post_folders","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/wf_post_folders?post=1060"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}