Mod\u0159\u00ed veleob\u0159i \u2013 hv\u011bzdy mnohon\u00e1sobn\u011b v\u011bt\u0161\u00ed a hmotn\u011bj\u0161\u00ed ne\u017e Slunce \u2013 proch\u00e1zej\u00ed dramatick\u00fdmi prom\u011bnami b\u011bhem sv\u00e9ho \u017eivota. Nov\u00e1 studie vyu\u017e\u00edvaj\u00edc\u00ed dru\u017eici TESS zkoum\u00e1, jak se tyto hv\u011bzdy vyv\u00edjej\u00ed a jak\u00e9 informace lze vyt\u011b\u017eit z jejich prom\u011bnlivosti. D\u00edky podrobn\u00e9 anal\u00fdze jedna\u010dty\u0159iceti t\u011bchto hv\u011bzd z\u00edsk\u00e1v\u00e1me nov\u00e9 poznatky o jejich vnit\u0159n\u00ed stavb\u011b, rotaci, pulsac\u00edch i z\u00e1hadn\u00e9m \u0161umu n\u00edzk\u00fdch frekvenc\u00ed, jeho\u017e p\u016fvod st\u00e1le unik\u00e1 jist\u00e9mu vysv\u011btlen\u00ed.<\/p>\n\n\n\n
Mod\u0159\u00ed veleob\u0159i jsou jedny z nejhmotn\u011bj\u0161\u00edch a nejz\u00e1\u0159iv\u011bj\u0161\u00edch hv\u011bzd v Galaxii. Ve sv\u00e9m v\u00fdvoji se nach\u00e1zej\u00ed mezi hlavn\u00ed posloupnost\u00ed, kde hv\u011bzdy spaluj\u00ed vod\u00edk v j\u00e1d\u0159e, a pozd\u011bj\u0161\u00edmi stadii vedouc\u00edmi ke kolapsu j\u00e1dra a potenci\u00e1ln\u011b i explozi supernovy. B\u011bhem tohoto mezistupn\u011b se projevuj\u00ed jako velmi sv\u00edtiv\u00e9 objekty. P\u0159esto jejich po\u010det v pozorovan\u00fdch vzorc\u00edch neodpov\u00edd\u00e1 p\u0159edpov\u011bd\u00edm tradi\u010dn\u00edch model\u016f hv\u011bzdn\u00e9ho v\u00fdvoje, ve skute\u010dnosti jich pozorujeme mnohem v\u00edce, ne\u017e bychom m\u011bli. Tento tzv. \u201eprobl\u00e9m modr\u00fdch veleobr\u016f\u201c nazna\u010duje, \u017ee hv\u011bzdy se b\u011bhem \u017eivota vyv\u00edjej\u00ed slo\u017eit\u011bji, ne\u017e si mysl\u00edme. Mohou se nap\u0159\u00edklad vracet do \u201emodr\u00e9ho\u201c stavu po f\u00e1zi rud\u00e9ho veleobra (tzv. post-RSG hv\u011bzdy), proch\u00e1zet interakcemi v bin\u00e1rn\u00edch syst\u00e9mech, nebo se st\u00e1t veleobry po slou\u010den\u00ed s jinou hv\u011bzdou. Variabilita jejich jasnosti \u2013 a\u0165 u\u017e pravideln\u00e1 nebo stochastick\u00e1 \u2013 pak slou\u017e\u00ed jako diagnostick\u00fd n\u00e1stroj, kter\u00fd odhaluje fyzik\u00e1ln\u00ed procesy odehr\u00e1vaj\u00edc\u00ed se pod povrchem t\u011bchto hv\u011bzd.<\/p>\n\n\n\n
T\u00fdm astronom\u016f veden\u00fd Michalisem Kourniotisem ze Stel\u00e1rn\u00edho odd\u011blen\u00ed ASU se zam\u011b\u0159il na jedna\u010dty\u0159icet modr\u00fdch veleobr\u016f v Ml\u00e9\u010dn\u00e9 dr\u00e1ze, jejich\u017e fyzik\u00e1ln\u00ed parametry byly d\u0159\u00edve ur\u010deny pomoc\u00ed spektroskopie. Hlavn\u00edm n\u00e1strojem nov\u00e9 studie byla dru\u017eice TESS, kter\u00e1 prim\u00e1rn\u011b hled\u00e1 exoplanety, ale z\u00e1rove\u0148 poskytuje mimo\u0159\u00e1dn\u011b p\u0159esn\u00e1 sv\u011bteln\u00e1 data pro stovky tis\u00edc hv\u011bzd. Auto\u0159i pe\u010dliv\u011b analyzovali sv\u011bteln\u00e9 k\u0159ivky (tedy v\u00fdvoj zm\u011bn jasnosti v \u010dase) jednotliv\u00fdch hv\u011bzd, a to jak pomoc\u00ed hotov\u00fdch datov\u00fdch produkt\u016f, tak i vlastn\u00edm zpracov\u00e1n\u00edm v\u00fd\u0159ez\u016f z obrazov\u00fdch pol\u00ed dru\u017eice.<\/p>\n\n\n\n
pokra\u010dov\u00e1n\u00ed: web ASU<\/a><\/p>\n\n\n\n Hertzsprung\u016fv\u2013Russell\u016fv diagram zachycuj\u00edc\u00ed modelov\u00fd v\u00fdvoj velmi hmotn\u00fdch hv\u011bzd. V grafu je vyzna\u010dena poloha jedna\u010dty\u0159iceti studovan\u00fdch modr\u00fdch obr\u016f spole\u010dn\u011b s v\u00fdvojov\u00fdmi stopami hv\u011bzdn\u00fdch model\u016f pro hv\u011bzdy s hmotnostmi mezi 12 a 120 hmotnostmi Slunce. \u010cern\u00e9 kru\u017enice ve vzorku zv\u00fdraz\u0148uj\u00ed hv\u011bzdy typu \u03b1 Cygni.<\/p>\n\n\n\n <\/p>\n","protected":false},"excerpt":{"rendered":" Mod\u0159\u00ed veleob\u0159i \u2013 hv\u011bzdy mnohon\u00e1sobn\u011b v\u011bt\u0161\u00ed a hmotn\u011bj\u0161\u00ed ne\u017e Slunce \u2013 proch\u00e1zej\u00ed dramatick\u00fdmi prom\u011bnami b\u011bhem sv\u00e9ho \u017eivota. Nov\u00e1 studie vyu\u017e\u00edvaj\u00edc\u00ed dru\u017eici TESS zkoum\u00e1, jak se tyto<\/p>\n","protected":false},"author":1,"featured_media":3428,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[37,32],"tags":[],"class_list":["post-3426","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-horke-hvezdy","category-novinky"],"_links":{"self":[{"href":"https:\/\/stel.asu.cas.cz\/cs\/wp-json\/wp\/v2\/posts\/3426","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/stel.asu.cas.cz\/cs\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/stel.asu.cas.cz\/cs\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/stel.asu.cas.cz\/cs\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/stel.asu.cas.cz\/cs\/wp-json\/wp\/v2\/comments?post=3426"}],"version-history":[{"count":4,"href":"https:\/\/stel.asu.cas.cz\/cs\/wp-json\/wp\/v2\/posts\/3426\/revisions"}],"predecessor-version":[{"id":3432,"href":"https:\/\/stel.asu.cas.cz\/cs\/wp-json\/wp\/v2\/posts\/3426\/revisions\/3432"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/stel.asu.cas.cz\/cs\/wp-json\/wp\/v2\/media\/3428"}],"wp:attachment":[{"href":"https:\/\/stel.asu.cas.cz\/cs\/wp-json\/wp\/v2\/media?parent=3426"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/stel.asu.cas.cz\/cs\/wp-json\/wp\/v2\/categories?post=3426"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/stel.asu.cas.cz\/cs\/wp-json\/wp\/v2\/tags?post=3426"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}Popis obr\u00e1zku<\/h4>\n\n\n\n
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