{"id":3968,"date":"2026-02-04T17:45:34","date_gmt":"2026-02-04T16:45:34","guid":{"rendered":"https:\/\/www-new.ias.u-psud.fr\/?p=3968"},"modified":"2026-09-25T13:20:17","modified_gmt":"2026-09-25T11:20:17","slug":"origine-de-leau-du-systeme-solaire-interne-la-composition-isotopique-initiale-de-lhydrogene-enfin-devoilee","status":"publish","type":"post","link":"https:\/\/www.ias.u-psud.fr\/index.php\/2026\/02\/04\/origine-de-leau-du-systeme-solaire-interne-la-composition-isotopique-initiale-de-lhydrogene-enfin-devoilee\/","title":{"rendered":"Origine de l&rsquo;eau du syst\u00e8me solaire interne : la composition isotopique initiale de l&rsquo;hydrog\u00e8ne enfin d\u00e9voil\u00e9e !"},"content":{"rendered":"\t\t<div data-elementor-type=\"wp-post\" data-elementor-id=\"3968\" class=\"elementor elementor-3968\" data-elementor-post-type=\"post\">\n\t\t\t\t<div class=\"elementor-element elementor-element-365d0f3 e-flex e-con-boxed e-con e-parent\" data-id=\"365d0f3\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t\t\t\t<div class=\"e-con-inner\">\n\t\t\t\t<div class=\"elementor-element elementor-element-84ab3f5 elementor-widget elementor-widget-theme-post-featured-image elementor-widget-image\" data-id=\"84ab3f5\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"theme-post-featured-image.default\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<img fetchpriority=\"high\" decoding=\"async\" width=\"817\" height=\"612\" src=\"https:\/\/www.ias.u-psud.fr\/wp-content\/uploads\/2026\/09\/202202-eau-fig1-fr.png\" class=\"attachment-large size-large wp-image-3970\" alt=\"\" srcset=\"https:\/\/www.ias.u-psud.fr\/wp-content\/uploads\/2026\/09\/202202-eau-fig1-fr.png 817w, https:\/\/www.ias.u-psud.fr\/wp-content\/uploads\/2026\/09\/202202-eau-fig1-fr-300x225.png 300w, https:\/\/www.ias.u-psud.fr\/wp-content\/uploads\/2026\/09\/202202-eau-fig1-fr-768x575.png 768w\" sizes=\"(max-width: 817px) 100vw, 817px\" \/>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t<div class=\"elementor-element elementor-element-f4f600f e-flex e-con-boxed e-con e-parent\" data-id=\"f4f600f\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t\t\t\t<div class=\"e-con-inner\">\n\t\t\t\t<div class=\"elementor-element elementor-element-7ce05c8 elementor-widget elementor-widget-text-editor\" data-id=\"7ce05c8\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t\t\t\t\t\t<p>Figure 1 : Repr\u00e9sentation sch\u00e9matique de l&rsquo;apport d&rsquo;eau interstellaire dans les r\u00e9gions les plus internes du syst\u00e8me solaire alors que le disque protoplan\u00e9taire est encore en formation, nourri par l&rsquo;enveloppe interstellaire en cours d&rsquo;effondrement. Vue en coupe. 1 unit\u00e9 astronomique = distance Terre-Soleil.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-63f7b05 elementor-widget elementor-widget-theme-post-title elementor-page-title elementor-widget-heading\" data-id=\"63f7b05\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"theme-post-title.default\">\n\t\t\t\t\t<h1 class=\"elementor-heading-title elementor-size-default\">Origine de l&rsquo;eau du syst\u00e8me solaire interne : la composition isotopique initiale de l&rsquo;hydrog\u00e8ne enfin d\u00e9voil\u00e9e !<\/h1>\t\t\t\t<\/div>\n\t\t<div class=\"elementor-element elementor-element-9b7c05e e-con e-atomic-element e-flexbox-base e-9b7c05e-607ee4c \" data-id=\"9b7c05e\" data-element_type=\"e-flexbox\" data-e-type=\"e-flexbox\" data-interaction-id=\"9b7c05e\">\n    \t\t<div class=\"elementor-element elementor-element-d72e17c elementor-widget elementor-widget-text-editor\" data-id=\"d72e17c\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t\t\t\t\t\t<p>Les interactions eau-roche sont essentielles dans la formation des plan\u00e8tes et notamment celle de la Terre. De fait, l&rsquo;origine de l&rsquo;eau dans les objets du syst\u00e8me solaire a toujours \u00e9t\u00e9 abondamment \u00e9tudi\u00e9e.<\/p><p>La composition isotopique de l&rsquo;hydrog\u00e8ne et de l&rsquo;oxyg\u00e8ne qui la composent est en particulier un traceur cl\u00e9 de ses sources. La composition isotopique de l&rsquo;hydrog\u00e8ne de l&rsquo;eau des objets plan\u00e9taires telluriques est interm\u00e9diaire entre celle de l&rsquo;eau interstellaire tr\u00e8s riche en deut\u00e9rium et celle de l&rsquo;hydrog\u00e8ne gazeux appauvri en deut\u00e9rium par les r\u00e9actions nucl\u00e9aires dans les \u00e9toiles. Cette composition particuli\u00e8re est habituellement expliqu\u00e9e par un m\u00e9lange entre de l&rsquo;eau interstellaire issue des r\u00e9gions externes froides du syst\u00e8me solaire et de l&rsquo;hydrog\u00e8ne solaire issu des r\u00e9gions internes chaudes. C&rsquo;est sur cette composition que s&rsquo;appuie le mod\u00e8le dominant d&rsquo;une origine tardive de l&rsquo;eau sur Terre par un bombardement com\u00e9taire ou ast\u00e9ro\u00efdal. Cependant, pour valider tous ces mod\u00e8les il restait jusqu&rsquo;\u00e0 pr\u00e9sent une inconnue fondamentale : la composition isotopique initiale de l&rsquo;eau du syst\u00e8me solaire, tout particuli\u00e8rement dans les r\u00e9gions internes du syst\u00e8me solaire dans lesquelles se sont form\u00e9es les briques des plan\u00e8tes telluriques.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\n<\/div>\n\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t<div class=\"elementor-element elementor-element-5612ae1 e-flex e-con-boxed e-con e-parent\" data-id=\"5612ae1\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t\t\t\t<div class=\"e-con-inner\">\n\t\t<div class=\"elementor-element elementor-element-8d2c731 e-con e-atomic-element e-flexbox-base e-8d2c731-bc6f834 \" data-id=\"8d2c731\" data-element_type=\"e-flexbox\" data-e-type=\"e-flexbox\" data-interaction-id=\"8d2c731\">\n    \t\t<div class=\"elementor-element elementor-element-10d0162 elementor-widget elementor-widget-text-editor\" data-id=\"10d0162\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t\t\t\t\t\t<p>Nous avons donc mesur\u00e9 la composition isotopique de l&rsquo;hydrog\u00e8ne de l&rsquo;une des plus vieilles roches du syst\u00e8me solaire, une inclusion m\u00e9t\u00e9oritique riche en calcium et aluminium (CAI) en utilisant une m\u00e9thodologie innovante mise au point pour cette \u00e9tude afin d&rsquo;acc\u00e9der \u00e0 la composition isotopique de min\u00e9raux microm\u00e9triques pauvres en hydrog\u00e8ne et form\u00e9s \u00e0 haute temp\u00e9rature dans le disque protoplan\u00e9taire interne. Nos r\u00e9sultats montrent la pr\u00e9servation de deux compositions isotopiques diff\u00e9rentes dans certains micro-min\u00e9raux :<\/p><ol><li>une composition isotopique solaire presque d\u00e9pourvue de deut\u00e9rium est observ\u00e9e dans les min\u00e9raux r\u00e9duits condens\u00e9s directement \u00e0 haute temp\u00e9rature.<\/li><li>une composition isotopique terrestre est observ\u00e9e dans des min\u00e9raux oxyd\u00e9s avant leur incorporation dans la CAI.<\/li><\/ol><p>En conclusion, cette dichotomie traduit l&rsquo;existence de deux r\u00e9servoirs gazeux d\u00e8s la formation des CAIs, c&rsquo;est-\u00e0-dire dans les premiers 200 000 ans du syst\u00e8me solaire, avant m\u00eame la formation des premiers embryons plan\u00e9taires. L&rsquo;un de ces r\u00e9servoirs est le gaz solaire \u00e0 l&rsquo;origine de toute la mati\u00e8re du syst\u00e8me solaire, mesur\u00e9 directement pour la premi\u00e8re fois dans une m\u00e9t\u00e9orite. Le second est un gaz enrichi en vapeur d&rsquo;eau, ayant d&#8217;embl\u00e9e la composition isotopique de la Terre. Sa formation peut s&rsquo;expliquer par un apport massif d&rsquo;eau interstellaire dans les r\u00e9gions internes chaudes du syst\u00e8me solaire lors de l&rsquo;effondrement de l&rsquo;enveloppe interstellaire et de la formation du disque protoplan\u00e9taire. Son existence pr\u00e9coce implique qu&rsquo;aucun apport tardif n&rsquo;est plus n\u00e9cessaire pour expliquer la composition isotopique de l&rsquo;eau des oc\u00e9ans terrestres, les briques des plan\u00e8tes telluriques s&rsquo;\u00e9tant form\u00e9es dans un gaz ayant d\u00e9j\u00e0 cette composition. L&rsquo;apport interstellaire \u00e0 l&rsquo;origine de l&rsquo;eau plan\u00e9taire dans le syst\u00e8me solaire est sans doute \u00e9galement \u00e0 l&rsquo;origine de la plupart des volatils plan\u00e9taires, tels que l&rsquo;oxyg\u00e8ne et l&rsquo;azote.<\/p><p>Les laboratoires impliqu\u00e9s sont l\u2019IMPMC (Sorbonne Universit\u00e9), l\u2019IAS (Universit\u00e9 Paris-Saclay), le NIMBE (CEA- Universit\u00e9 Paris-Saclay) et l\u2019ICMMO (Universit\u00e9 Paris-Saclay).<\/p><p><strong>R\u00e9f\u00e9rence<\/strong> :\u00a0<br \/>J. Al\u00e9on, D. Levy, A. Al\u00e9on-Toppani, H. Bureau, H. Khodja, and F. Brisset (2022) Determination of the initial hydrogen isotopic composition of the solar system, Nature Astronomy, released 3 february.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\n<\/div>\n\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t","protected":false},"excerpt":{"rendered":"<p>Les interactions eau-roche sont essentielles dans la formation des plan\u00e8tes et notamment celle de la Terre. <\/p>\n","protected":false},"author":3,"featured_media":3970,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"elementor_header_footer","format":"standard","meta":{"inline_featured_image":false,"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[5,24],"tags":[],"class_list":["post-3968","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-news-scientifiques-home","category-caps-scientifiques"],"_links":{"self":[{"href":"https:\/\/www.ias.u-psud.fr\/index.php\/wp-json\/wp\/v2\/posts\/3968","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.ias.u-psud.fr\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.ias.u-psud.fr\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.ias.u-psud.fr\/index.php\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/www.ias.u-psud.fr\/index.php\/wp-json\/wp\/v2\/comments?post=3968"}],"version-history":[{"count":14,"href":"https:\/\/www.ias.u-psud.fr\/index.php\/wp-json\/wp\/v2\/posts\/3968\/revisions"}],"predecessor-version":[{"id":4206,"href":"https:\/\/www.ias.u-psud.fr\/index.php\/wp-json\/wp\/v2\/posts\/3968\/revisions\/4206"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.ias.u-psud.fr\/index.php\/wp-json\/wp\/v2\/media\/3970"}],"wp:attachment":[{"href":"https:\/\/www.ias.u-psud.fr\/index.php\/wp-json\/wp\/v2\/media?parent=3968"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ias.u-psud.fr\/index.php\/wp-json\/wp\/v2\/categories?post=3968"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ias.u-psud.fr\/index.php\/wp-json\/wp\/v2\/tags?post=3968"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}