{"id":27,"date":"2022-05-24T22:49:22","date_gmt":"2022-05-24T20:49:22","guid":{"rendered":"http:\/\/actionsciencejargeau.fr\/?page_id=27"},"modified":"2024-08-13T19:14:10","modified_gmt":"2024-08-13T17:14:10","slug":"panneau3","status":"publish","type":"page","link":"https:\/\/actionsciencejargeau.fr\/index.php\/accueil\/cdu\/etape1\/panneau3\/","title":{"rendered":"La naissance des premi\u00e8res \u00e9toiles"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\"><\/p>\n\n\n\n<div class=\"wp-block-group has-luminous-dusk-gradient-background has-background is-nowrap is-layout-flex wp-container-core-group-is-layout-8f761849 wp-block-group-is-layout-flex\">\n<div class=\"wp-block-group is-vertical is-layout-flex wp-container-core-group-is-layout-4fc3f8e1 wp-block-group-is-layout-flex\">\n<div class=\"wp-block-group is-vertical is-layout-flex wp-container-core-group-is-layout-4fc3f8e1 wp-block-group-is-layout-flex\">\n<figure class=\"wp-block-audio\"><audio controls src=\"http:\/\/actionsciencejargeau.fr\/wp-content\/uploads\/2022\/07\/Et1-3-1.mp3\"><\/audio><\/figure>\n\n\n\n<div class=\"wp-block-buttons is-layout-flex wp-block-buttons-is-layout-flex\">\n<div class=\"wp-block-button\"><a class=\"wp-block-button__link wp-element-button\">Pr\u00e9c\u00e9dent<\/a><\/div>\n\n\n\n<div class=\"wp-block-button\"><a class=\"wp-block-button__link wp-element-button\">Suivant<\/a><\/div>\n<\/div>\n<\/div>\n\n\n\n<div class=\"wp-block-group is-vertical is-layout-flex wp-container-core-group-is-layout-4fc3f8e1 wp-block-group-is-layout-flex\">\n<p class=\"has-small-font-size wp-block-paragraph\">Dans cet Univers naissant s\u2019\u00e9tend ce gaz d\u2019atomes primaires, compos\u00e9 de Be, Li et He mais surtout de beaucoup, beaucoup d\u2019hydrog\u00e8ne&nbsp;!<br>Les forces que nous avons vu, vont continuer \u00e0 s\u2019exprimer. Les atomes passant \u00e0 c\u00f4t\u00e9 d\u2019autres atomes, vont s\u2019attirer.. cela va commencer \u00e0 former des grumeaux, puis les grumeaux vont grossir, grossir, grossir, grossir tellement que des masses de mati\u00e8re (et surtout de l\u2019hydrog\u00e8ne) vont se former. Sous l\u2019effet de la gravit\u00e9, la pression au c\u0153ur de la masse va augmenter, donc la temp\u00e9rature va augmenter. La temp\u00e9rature sera telle qu\u2019elle va provoquer une r\u00e9action nucl\u00e9aire&nbsp;: la fusion des atomes d\u2019hydrog\u00e8ne. \u00c7a y est, l\u2019\u00e9toile vient de na\u00eetre. En fusionnant, l\u2019hydrog\u00e8ne formera de l\u2019h\u00e9lium et beaucoup d\u2019\u00e9nergie. C\u2019est cette \u00e9nergie que nous recevons sur terre&nbsp;! L\u2019\u00e9nergie qui se d\u00e9gage provoque la dilatation de l\u2019\u00e9toile, alors que la gravit\u00e9 provoque la contraction.<\/p>\n\n\n\n<p class=\"has-small-font-size wp-block-paragraph\">A cette p\u00e9riode, parce qu\u2019il n\u2019y a que de l\u2019hydrog\u00e8ne et de l\u2019h\u00e9lium, les \u00e9toiles n\u2019ont pas de plan\u00e8tes telluriques! Il n\u2019y a que des \u00e9toiles qui brillent dans l\u2019Univers, mais il n\u2019y a personne pour les regarder. Dans l\u2019\u00e9toile, d\u2019autres atomes vont se former&nbsp;: N, O, S, soit les 22 premiers \u00e9l\u00e9ments chimiques jusqu\u2019au fer.<\/p>\n\n\n\n<p class=\"has-small-font-size wp-block-paragraph\">Selon la quantit\u00e9 de mati\u00e8re disponible, l\u2019\u00e9toile aura une taille plus ou moins grande.<br>On voit sur ce graphe, la distribution de la taille des \u00e9toiles en fonction de leur \u00e9clat et de leur temp\u00e9rature.<br>Notre Soleil n\u2019est que de taille tr\u00e8s modeste. Il y a des \u00e9toiles gigantesques&nbsp;!<br>Deneb, la queue du cygne, B\u00e9telgeuse, l\u2019\u00e9paule d\u2019Orion ou Arcturus dans le Bouvier en font parti.<br>La couleur de l\u2019\u00e9toile est importante&nbsp;; lorsqu\u2019elle appara\u00eet rouge, elle est plus froide. Les bleues sont plus chaude.<\/p>\n\n\n\n<p class=\"has-small-font-size wp-block-paragraph\">De 4 \u00e9l\u00e9ments chimiques, cr\u00e9\u00e9s juste apr\u00e8s le Big Bang, les \u00e9toiles fabriquent 22 autres \u00e9l\u00e9ments. Le fer cl\u00f4t ce fantastique laboratoire!<\/p>\n<\/div>\n<\/div>\n\n\n\n<figure class=\"wp-block-image size-full\"><img fetchpriority=\"high\" decoding=\"async\" width=\"451\" height=\"856\" src=\"http:\/\/actionsciencejargeau.fr\/wp-content\/uploads\/2022\/07\/image-39.png\" alt=\"\" class=\"wp-image-333\" srcset=\"https:\/\/actionsciencejargeau.fr\/wp-content\/uploads\/2022\/07\/image-39.png 451w, https:\/\/actionsciencejargeau.fr\/wp-content\/uploads\/2022\/07\/image-39-158x300.png 158w\" sizes=\"(max-width: 451px) 100vw, 451px\" \/><\/figure>\n<\/div>\n\n\n\n<div class=\"wp-block-columns alignwide has-luminous-dusk-gradient-background has-background is-layout-flex wp-container-core-columns-is-layout-8f761849 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\" style=\"flex-basis:59%\">\n<div class=\"wp-block-group\" style=\"padding-top:2em;padding-right:2em;padding-bottom:2em;padding-left:2em\"><div class=\"wp-block-group__inner-container is-layout-flow wp-block-group-is-layout-flow\">\n<p class=\"has-text-align-center wp-block-paragraph\" style=\"font-size:36px;line-height:1.2\"><strong>Des \u00e9toiles ? <\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Les particules et atomes se g\u00e9n\u00e8rent au sein des \u00e9toiles, mais comment sont n\u00e9es les \u00e9toiles<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Continuons notre route avec Henry pour d\u00e9couvrir les premi\u00e8res \u00e9toiles<\/p>\n\n\n\n<figure class=\"wp-block-audio\"><audio controls src=\"http:\/\/actionsciencejargeau.fr\/wp-content\/uploads\/2022\/07\/Et1-3.mp3\"><\/audio><\/figure>\n\n\n\n<div class=\"wp-block-group is-nowrap is-layout-flex wp-container-core-group-is-layout-8f761849 wp-block-group-is-layout-flex\">\n<div class=\"wp-block-buttons is-layout-flex wp-block-buttons-is-layout-flex\">\n<div class=\"wp-block-button\"><a class=\"wp-block-button__link wp-element-button\" href=\"http:\/\/actionsciencejargeau.fr\/index.php\/accueil\/cdu\/etape1\/panneau2\/\">pr\u00e9c\u00e9dent<\/a><\/div>\n<\/div>\n\n\n\n<div class=\"wp-block-buttons is-layout-flex wp-block-buttons-is-layout-flex\">\n<div class=\"wp-block-button\"><a class=\"wp-block-button__link wp-element-button\" href=\"http:\/\/actionsciencejargeau.fr\/index.php\/accueil\/cdu\/etape1\/panneau4\/\">suivant<\/a><\/div>\n<\/div>\n<\/div>\n\n\n\n<figure class=\"wp-block-image size-full is-style-rounded\"><img decoding=\"async\" width=\"700\" height=\"414\" src=\"http:\/\/actionsciencejargeau.fr\/wp-content\/uploads\/2022\/07\/eso1337a.jpg\" alt=\"\" class=\"wp-image-125\" srcset=\"https:\/\/actionsciencejargeau.fr\/wp-content\/uploads\/2022\/07\/eso1337a.jpg 700w, https:\/\/actionsciencejargeau.fr\/wp-content\/uploads\/2022\/07\/eso1337a-300x177.jpg 300w\" sizes=\"(max-width: 700px) 100vw, 700px\" \/><figcaption class=\"wp-element-caption\">This image tracks the life of a Sun-like star, from its birth on the left side of the frame to its evolution into a red giant star on the right. On the left the star is seen as a protostar, embedded within a dusty disc of material as it forms. It later becomes a star like our Sun. After spending the majority of its life in this stage, the star&rsquo;s core begins to gradually heat up, the star expands and becomes redder until it transforms into a red giant. Following this stage, the star will push its outer layers into the surrounding space to form an object known as a planetary nebula, while the core of the star itself will cool into a small, dense remnant called a white dwarf star. Marked on the lower timeline are where our Sun and solar twins 18 Sco and HIP 102152 are in this life cycle. The Sun is 4.6 billion years old and 18 Sco is 2.9 billion years old, while the oldest solar twin is some 8.2 billion years old \u2014 &nbsp;the oldest solar twin ever identified. By studying HIP 102152, we can get a glimpse of what the future holds for our Sun. This image is illustrative; the ages, sizes, and colours are approximate (not to scale). The protostar stage, on the far left of this image, can be some 2000  times larger than our Sun. The red giant stage, on the far right of this  image, can be some 100 times larger than the Sun.<\/figcaption><\/figure>\n<\/div><\/div>\n<\/div>\n\n\n\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\" style=\"flex-basis:41%\">\n<figure class=\"wp-block-image size-full\"><img decoding=\"async\" width=\"700\" height=\"422\" src=\"http:\/\/actionsciencejargeau.fr\/wp-content\/uploads\/2022\/07\/eso1726b.jpg\" alt=\"\" class=\"wp-image-123\" srcset=\"https:\/\/actionsciencejargeau.fr\/wp-content\/uploads\/2022\/07\/eso1726b.jpg 700w, https:\/\/actionsciencejargeau.fr\/wp-content\/uploads\/2022\/07\/eso1726b-300x181.jpg 300w\" sizes=\"(max-width: 700px) 100vw, 700px\" \/><figcaption class=\"wp-element-caption\">This artist\u2019s impression shows the red supergiant star Antares in the constellation of Scorpius. Using ESO\u2019s Very Large Telescope Interferometer astronomers have constructed the most detailed image ever of this, or any star other than the Sun. Using the same data they have also made the first map of the velocities of material the atmosphere of a star other than the Sun.<\/figcaption><\/figure>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"700\" height=\"438\" src=\"http:\/\/actionsciencejargeau.fr\/wp-content\/uploads\/2022\/07\/eso1540a.jpg\" alt=\"\" class=\"wp-image-124\" srcset=\"https:\/\/actionsciencejargeau.fr\/wp-content\/uploads\/2022\/07\/eso1540a.jpg 700w, https:\/\/actionsciencejargeau.fr\/wp-content\/uploads\/2022\/07\/eso1540a-300x188.jpg 300w\" sizes=\"(max-width: 700px) 100vw, 700px\" \/><figcaption class=\"wp-element-caption\">This artist\u2019s impression shows VFTS 352 \u2014 the hottest and most massive double star system to date where the two components are in contact and sharing material. The two stars in this extreme system lie about 160 000 light-years from Earth in the Large Magellanic Cloud. This intriguing system could be heading for a dramatic end, either with the formation of a single giant star or as a future binary black hole.<\/figcaption><\/figure>\n<\/div>\n<\/div>\n\n\n\n<p class=\"wp-block-paragraph\"><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Dans cet Univers naissant s\u2019\u00e9tend ce gaz d\u2019atomes primaires, compos\u00e9 de Be, Li et He mais surtout de beaucoup, beaucoup d\u2019hydrog\u00e8ne&nbsp;!Les forces que nous avons vu, vont continuer \u00e0 s\u2019exprimer. [&hellip;]<\/p>\n","protected":false},"author":3,"featured_media":0,"parent":14,"menu_order":3,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-27","page","type-page","status-publish","hentry","entry"],"_links":{"self":[{"href":"https:\/\/actionsciencejargeau.fr\/index.php\/wp-json\/wp\/v2\/pages\/27","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/actionsciencejargeau.fr\/index.php\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/actionsciencejargeau.fr\/index.php\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/actionsciencejargeau.fr\/index.php\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/actionsciencejargeau.fr\/index.php\/wp-json\/wp\/v2\/comments?post=27"}],"version-history":[{"count":5,"href":"https:\/\/actionsciencejargeau.fr\/index.php\/wp-json\/wp\/v2\/pages\/27\/revisions"}],"predecessor-version":[{"id":555,"href":"https:\/\/actionsciencejargeau.fr\/index.php\/wp-json\/wp\/v2\/pages\/27\/revisions\/555"}],"up":[{"embeddable":true,"href":"https:\/\/actionsciencejargeau.fr\/index.php\/wp-json\/wp\/v2\/pages\/14"}],"wp:attachment":[{"href":"https:\/\/actionsciencejargeau.fr\/index.php\/wp-json\/wp\/v2\/media?parent=27"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}