{"id":43,"date":"2022-05-24T22:50:59","date_gmt":"2022-05-24T20:50:59","guid":{"rendered":"http:\/\/actionsciencejargeau.fr\/?page_id=43"},"modified":"2022-07-14T19:12:09","modified_gmt":"2022-07-14T17:12:09","slug":"panneau4","status":"publish","type":"page","link":"https:\/\/actionsciencejargeau.fr\/index.php\/accueil\/cdu\/etape1\/panneau4\/","title":{"rendered":"Les \u00e9toiles meurent"},"content":{"rendered":"\n<div class=\"wp-block-group has-luminous-dusk-gradient-background has-background is-nowrap is-layout-flex wp-container-core-group-is-layout-ad2f72ca wp-block-group-is-layout-flex\">\n<div class=\"wp-block-group is-vertical is-layout-flex wp-container-core-group-is-layout-8cf370e7 wp-block-group-is-layout-flex\">\n<figure class=\"wp-block-audio\"><audio controls src=\"http:\/\/actionsciencejargeau.fr\/wp-content\/uploads\/2022\/07\/Et1-4-1.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\" href=\"http:\/\/actionsciencejargeau.fr\/index.php\/accueil\/cdu\/etape1\/panneau3\/\">Pr\u00e9c\u00e9dent<\/a><\/div>\n\n\n\n<div class=\"wp-block-button\"><a class=\"wp-block-button__link\" href=\"http:\/\/actionsciencejargeau.fr\/index.php\/accueil\/cdu\/etape2\/panneau1\/\">Suivant<\/a><\/div>\n<\/div>\n\n\n\n<p class=\"has-small-font-size\">Il est possible de pr\u00e9dire la vie d\u2019une \u00e9toile \u00e0 partir de sa taille. Ainsi, 3 grandes cat\u00e9gories ont \u00e9t\u00e9 identifi\u00e9es&nbsp;:<br>1- les \u00e9toiles les plus petites vont se consumer r\u00e9guli\u00e8rement jusqu\u2019\u00e0 s\u2019\u00e9teindre en s\u2019effondrant<br>2- Notre Soleil est une \u00e9toile de taille moyenne, juste au milieu de sa vie. Il va continuer \u00e0 se dilater pour devenir une g\u00e9ante rouge, puis s\u2019effondrer pour finir en naine blanche&nbsp;; ce sera un astre gros comme la terre mais avec la masse du soleil, mais sans activit\u00e9.<br>3- les plus grosses \u00e9toiles sont plus impressionnantes&nbsp;; elles finiront en supernova, puis pourront \u00e9voluer en \u00e9toile \u00e0 neutrons ou en trou noir<\/p>\n\n\n\n<p class=\"has-small-font-size\">Ce n\u2019est pas parce qu\u2019une \u00e9toile est grosse qu\u2019elle vivra plus longtemps, tout au contraire.<\/p>\n\n\n\n<p class=\"has-small-font-size\">L\u2019\u00e9toile se meurt. Elle a d\u00e9j\u00e0 fabriqu\u00e9 beaucoup d\u2019\u00e9l\u00e9ments, et elle finira en apoth\u00e9ose.<br>L\u2019\u00e9nergie lib\u00e9r\u00e9 lors de l\u2019explosion d\u2019une supernov\u00e6 est immense.<br>L\u2019\u00e9nergie de fusion de l\u2019hydrog\u00e8ne n\u2019est plus l\u00e0 pour inverser le sens de la force gravitationnelle, puisque le r\u00e9servoir est \u00e9puis\u00e9.<br>La force gravitationnelle est \u00e0 l\u2019origine de l\u2019explosion finale. C\u2019est l\u00e0 que les autres \u00e9l\u00e9ments que nous connaissons sont synth\u00e9tis\u00e9s par fusion nucl\u00e9aire.<\/p>\n\n\n\n<p class=\"has-small-font-size\">\u00c7a y est! Nous voyons enfin tous les \u00e9l\u00e9ments qui nous sont familiers sur notre Terre!<\/p>\n\n\n\n<p class=\"has-small-font-size\">Si la masse de l\u2019\u00e9toile est trop importante, alors il n\u2019y aura pas de supernova \u2026 mais un trou noir\u2026<br>Nous sommes des poussi\u00e8res d\u2019\u00e9toiles<br>Parce ce que la mati\u00e8re qui forme notre chaire a \u00e9t\u00e9 form\u00e9e par l\u2019\u00e9toile qui a donn\u00e9 naissance \u00e0 notre syst\u00e8me solaire<\/p>\n\n\n\n<p class=\"has-small-font-size\">Mais nous avons aussi besoin de la poussi\u00e8re de supernova pour donner la diversit\u00e9 des atomes formant notre Terre\u00a0!<br>Nous sommes des poussi\u00e8res de supernov\u00e6.<\/p>\n<\/div>\n\n\n\n<figure class=\"wp-block-image size-full\"><img fetchpriority=\"high\" decoding=\"async\" width=\"451\" height=\"854\" src=\"http:\/\/actionsciencejargeau.fr\/wp-content\/uploads\/2022\/07\/image-40.png\" alt=\"\" class=\"wp-image-338\" srcset=\"https:\/\/actionsciencejargeau.fr\/wp-content\/uploads\/2022\/07\/image-40.png 451w, https:\/\/actionsciencejargeau.fr\/wp-content\/uploads\/2022\/07\/image-40-158x300.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-9d6595d7 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\" style=\"font-size:36px;line-height:1.2\">Une \u00e9toile, \u00e7a peut mourir ?<\/p>\n\n\n\n<p>Et oui, les \u00e9toiles naissent, grandissent, puis meurent<\/p>\n\n\n\n<p>Continuons notre route avec Henry pour comprendre la vie des \u00e9toiles<\/p>\n\n\n\n<figure class=\"wp-block-audio\"><audio controls src=\"http:\/\/actionsciencejargeau.fr\/wp-content\/uploads\/2022\/07\/Et1-4.mp3\"><\/audio><\/figure>\n\n\n\n<div class=\"wp-block-group is-nowrap is-layout-flex wp-container-core-group-is-layout-ad2f72ca 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\" href=\"http:\/\/actionsciencejargeau.fr\/index.php\/accueil\/cdu\/etape1\/panneau3\/\">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\" href=\"http:\/\/actionsciencejargeau.fr\/index.php\/accueil\/cdu\/etape2\/panneau1\/\">suivant<\/a><\/div>\n<\/div>\n<\/div>\n\n\n\n<figure class=\"wp-block-image size-large is-style-rounded\"><img decoding=\"async\" width=\"1024\" height=\"1024\" src=\"http:\/\/actionsciencejargeau.fr\/wp-content\/uploads\/2022\/07\/tycho-1024x1024.jpg\" alt=\"\" class=\"wp-image-135\" srcset=\"https:\/\/actionsciencejargeau.fr\/wp-content\/uploads\/2022\/07\/tycho-1024x1024.jpg 1024w, https:\/\/actionsciencejargeau.fr\/wp-content\/uploads\/2022\/07\/tycho-300x300.jpg 300w, https:\/\/actionsciencejargeau.fr\/wp-content\/uploads\/2022\/07\/tycho-150x150.jpg 150w, https:\/\/actionsciencejargeau.fr\/wp-content\/uploads\/2022\/07\/tycho-768x769.jpg 768w, https:\/\/actionsciencejargeau.fr\/wp-content\/uploads\/2022\/07\/tycho.jpg 1041w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><figcaption>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-large is-style-rounded\"><img decoding=\"async\" width=\"1024\" height=\"749\" src=\"http:\/\/actionsciencejargeau.fr\/wp-content\/uploads\/2022\/07\/hubble_friday_07302015-1024x749.jpg\" alt=\"\" class=\"wp-image-133\" srcset=\"https:\/\/actionsciencejargeau.fr\/wp-content\/uploads\/2022\/07\/hubble_friday_07302015-1024x749.jpg 1024w, https:\/\/actionsciencejargeau.fr\/wp-content\/uploads\/2022\/07\/hubble_friday_07302015-300x219.jpg 300w, https:\/\/actionsciencejargeau.fr\/wp-content\/uploads\/2022\/07\/hubble_friday_07302015-768x561.jpg 768w, https:\/\/actionsciencejargeau.fr\/wp-content\/uploads\/2022\/07\/hubble_friday_07302015.jpg 1041w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><figcaption>A dying star\u2019s final moments are captured in this image from the NASA\/ESA Hubble Space Telescope. The death throes of this star may only last mere moments on a cosmological timescale, but this star\u2019s demise is still quite lengthy by our standards, lasting tens of thousands of years! The star\u2019s agony has culminated in a wonderful planetary nebula known as NGC 6565, a cloud of gas that was ejected from the star after strong stellar winds pushed the star\u2019s outer layers away into space. Once enough material was ejected, the star\u2019s luminous core was exposed and it began to produce ultraviolet radiation, exciting the surrounding gas to varying degrees and causing it to radiate in an attractive array of colours. These same colours can be seen in the famous and impressive Ring Nebula (heic1310), a prominent example of a nebula like this one. Planetary nebulae are illuminated for around 10 000 years before the central star begins to cool and shrink to become a white dwarf. When this happens, the star\u2019s light drastically diminishes and ceases to excite the surrounding gas, so the nebula fades from view. A version of this image was entered into the Hubble\u2019s Hidden Treasures basic image competition by contestant Matej Novak.<\/figcaption><\/figure>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"940\" src=\"http:\/\/actionsciencejargeau.fr\/wp-content\/uploads\/2022\/07\/potw1705a-1024x940.jpg\" alt=\"\" class=\"wp-image-134\" srcset=\"https:\/\/actionsciencejargeau.fr\/wp-content\/uploads\/2022\/07\/potw1705a-1024x940.jpg 1024w, https:\/\/actionsciencejargeau.fr\/wp-content\/uploads\/2022\/07\/potw1705a-300x276.jpg 300w, https:\/\/actionsciencejargeau.fr\/wp-content\/uploads\/2022\/07\/potw1705a-768x705.jpg 768w, https:\/\/actionsciencejargeau.fr\/wp-content\/uploads\/2022\/07\/potw1705a.jpg 1041w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><figcaption>The Calabash Nebula, pictured here \u2014 which has the technical name OH 231.8+04.2 \u2014 is a spectacular example of the death of a low-mass star like the Sun. This image taken by the NASA\/ESA Hubble Space Telescope shows the star going through a rapid transformation from a red giant to a planetary nebula, during which it blows its outer layers of gas and dust out into the surrounding space. The recently ejected material is spat out in opposite directions with immense speed \u2014 the gas shown in yellow is moving close to a million kilometres an hour. Astronomers rarely capture a star in this phase of its evolution because it occurs within the blink of an eye \u2014 in astronomical terms. Over the next thousand years the nebula is expected to evolve into a fully fledged planetary nebula. The nebula is also known as the Rotten Egg Nebula because it contains a lot of sulphur, an element that, when combined with other elements, smells like a rotten egg \u2014 but luckily, it resides over 5000 light-years away in the constellation of Puppis (The Poop deck).<\/figcaption><\/figure>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>Il est possible de pr\u00e9dire la vie d\u2019une \u00e9toile \u00e0 partir de sa taille. Ainsi, 3 grandes cat\u00e9gories ont \u00e9t\u00e9 identifi\u00e9es&nbsp;:1- les \u00e9toiles les plus petites vont se consumer r\u00e9guli\u00e8rement [&hellip;]<\/p>\n","protected":false},"author":3,"featured_media":0,"parent":14,"menu_order":4,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-43","page","type-page","status-publish","hentry","entry"],"_links":{"self":[{"href":"https:\/\/actionsciencejargeau.fr\/index.php\/wp-json\/wp\/v2\/pages\/43","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=43"}],"version-history":[{"count":5,"href":"https:\/\/actionsciencejargeau.fr\/index.php\/wp-json\/wp\/v2\/pages\/43\/revisions"}],"predecessor-version":[{"id":339,"href":"https:\/\/actionsciencejargeau.fr\/index.php\/wp-json\/wp\/v2\/pages\/43\/revisions\/339"}],"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=43"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}