{"id":261,"date":"2019-12-03T13:07:32","date_gmt":"2019-12-03T12:07:32","guid":{"rendered":"https:\/\/kids.esa.int\/esa_s_cheops_satellite_will_measure_the_sizes_of_exoplanets\/"},"modified":"2026-10-08T00:26:09","modified_gmt":"2026-10-07T22:26:09","slug":"esa_s_cheops_satellite_will_measure_the_sizes_of_exoplanets","status":"publish","type":"post","link":"https:\/\/kids.esa.int\/fr\/esa_s_cheops_satellite_will_measure_the_sizes_of_exoplanets\/","title":{"rendered":"Le satellite CHEOPS de l\u2019ESA va mesurer la taille des exoplan\u00e8tes"},"content":{"rendered":"<div class=\"lede\">\n<p>Avez-vous d\u00e9j\u00e0 observ\u00e9 le ciel la nuit, en vous demandant si d\u2019autres plan\u00e8tes se trouvaient au-del\u00e0 de notre syst\u00e8me solaire ? Des astronomes ont apport\u00e9 la preuve que de telles plan\u00e8tes existaient ! Nous les appelons les plan\u00e8tes extrasolaires, ou exoplan\u00e8tes. Des milliers de plan\u00e8tes extrasolaires ont \u00e9t\u00e9 d\u00e9couvertes \u00e0 ce jour, et nous allons continuer d\u2019en trouver \u00e0 mesure que nous poursuivrons nos recherches.<\/p>\n<p>Il est tr\u00e8s difficile de photographier les exoplan\u00e8tes. En effet, ces derni\u00e8res sont situ\u00e9es hors de notre syst\u00e8me solaire, \u00e0 des distances tr\u00e8s lointaines. Pour trouver des exoplan\u00e8tes, les astronomes doivent par cons\u00e9quent utiliser d\u2019autres techniques, par exemple via l'observation des \u00e9toiles qui tremblent dans l\u2019espace en raison de la gravit\u00e9 des exoplan\u00e8tes en orbite autour d\u2019elles. Cette m\u00e9thode, parmi d\u2019autres, ne nous aide pas seulement \u00e0 d\u00e9couvrir de nouvelles exoplan\u00e8tes. Elle permet \u00e9galement aux astronomes de calculer leur masse et leurs coordonn\u00e9es orbitales. Il ne nous manque plus aujourd\u2019hui qu\u2019un t\u00e9lescope capable de calculer la taille de ces exoplan\u00e8tes. C\u2019est l\u00e0 qu\u2019intervient la mission CHEOPS !<\/p>\n<\/div>\n<p>Lanc\u00e9 en d\u00e9cembre 2019, CHEOPS \u2013 dont le nom complet est CHaracterising ExOPlanet Satellite \u2013 est une mission de l'ESA destin\u00e9e \u00e0 nous aider \u00e0 mieux comprendre les exoplan\u00e8tes. Plut\u00f4t que de rechercher de nouvelles exoplan\u00e8tes, CHEOPS va \u00e9tudier celles que nous avons d\u00e9j\u00e0 d\u00e9couvertes et dont la masse a \u00e9t\u00e9 calcul\u00e9e.<\/p>\n<p>Le satellite de la mission CHEOPS sera dot\u00e9 d\u2019un photom\u00e8tre, un instrument de haute technologie extr\u00eamement sensible servant \u00e0 mesurer l\u2019intensit\u00e9 de la lumi\u00e8re. Quand une exoplan\u00e8te passera devant l\u2019\u00e9toile autour de laquelle elle orbite, cachant une petite partie de sa lumi\u00e8re, CHEOPS mesurera la baisse de luminosit\u00e9 de cette \u00e9toile. Cette variation de luminosit\u00e9 permettra aux scientifiques de la mission de calculer la taille de l\u2019exoplan\u00e8te ! En combinant ces informations aux donn\u00e9es relatives \u00e0 la masse, il sera alors possible de d\u00e9terminer la densit\u00e9 des exoplan\u00e8tes. Cela devrait \u00e9galement nous donner des indices sur la composition de ces plan\u00e8tes lointaines. Sont-elles compos\u00e9es de roches ou de gaz ? Peut-on y trouver des oc\u00e9ans ?<\/p>\n<figure class=\"wp-block-embed is-type-video\"><iframe src=\"https:\/\/www.youtube.com\/embed\/O9wm0IB3LMA\" width=\"560\" height=\"315\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"><\/iframe><\/figure>\n<figure class=\"wp-block-image size-large\" data-width=\"2500\" data-credit=\"ESA\" data-detail-url=\"https:\/\/www.esa.int\/ESA_Multimedia\/Images\/2019\/02\/What_kind_of_planets_will_Cheops_study\" 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\" style=\"max-width: 100%; height: auto;\" src=\"https:\/\/www.esa.int\/var\/esa\/storage\/images\/esa_multimedia\/images\/2019\/02\/what_kind_of_planets_will_cheops_study\/19220443-1-eng-GB\/What_kind_of_planets_will_Cheops_study.jpg\" alt=\"What kind of planets will Cheops study?\" \/><figcaption>Quel type de plan\u00e8tes Kh\u00e9ops va-t-il \u00e9tudier ?<\/figcaption><\/figure>\n<p>Gr\u00e2ce \u00e0 toutes ces informations, la communaut\u00e9 scientifique sera en mesure de dresser la liste des exoplan\u00e8tes susceptibles de poss\u00e9der une atmosph\u00e8re. Ces plan\u00e8tes deviendront alors des cibles privil\u00e9gi\u00e9es pour les astronomes de demain, qui utiliseront des t\u00e9lescopes plus puissants et des instruments plus sensibles pour \u00e9tudier ces mondes distants. Selon vous, quels secrets vont-ils percer avec l\u2019aide de CHEOPS ?<\/p>\n<p><i>Fait int\u00e9ressant : le photom\u00e8tre de CHEOPS est si sensible qu\u2019il permet d\u2019\u00e9tudier des exoplan\u00e8tes relativement petites <\/i>\u2013<i>\u00a0jusqu'\u00e0 la taille de Neptune ! <\/i><\/p>\n<p><b>\u00a0<\/b><\/p>","protected":false},"excerpt":{"rendered":"<p>Have you ever looked up at the night sky and wondered if there are other planets out there, beyond our Solar System? Astronomers have discovered that there are! We call [&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\/2019\/03\/cheops_satellite7\/19318953-2-eng-GB\/Cheops_satellite.jpg","esa_banner_description":"The CHEOPS satellite being tested before launch. It is 1.5 metres long, and weighs 280kg. Copyright: ESA - S. Corvaja","esa_banner_credit":"ESA \u2013 S. Corvaja","esa_banner_licence":"ESA Standard Licence","esa_banner_detail_url":"https:\/\/www.esa.int\/ESA_Multimedia\/Images\/2019\/03\/Cheops_satellite7","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-261","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\/261","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=261"}],"version-history":[{"count":6,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/posts\/261\/revisions"}],"predecessor-version":[{"id":4378,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/posts\/261\/revisions\/4378"}],"wp:attachment":[{"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/media?parent=261"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/categories?post=261"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/tags?post=261"},{"taxonomy":"panel","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/panel?post=261"},{"taxonomy":"language","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/language?post=261"},{"taxonomy":"age","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/age?post=261"},{"taxonomy":"duration","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/duration?post=261"},{"taxonomy":"resource_type","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/resource_type?post=261"},{"taxonomy":"audience","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/audience?post=261"},{"taxonomy":"wf_post_folders","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/wf_post_folders?post=261"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}