{"id":498820,"date":"2026-05-23T09:10:21","date_gmt":"2026-05-23T09:10:21","guid":{"rendered":"https:\/\/www.europesays.com\/ie\/498820\/"},"modified":"2026-05-23T09:10:21","modified_gmt":"2026-05-23T09:10:21","slug":"how-can-a-young-blue-giant-have-a-white-dwarf-companion-star","status":"publish","type":"post","link":"https:\/\/www.europesays.com\/ie\/498820\/","title":{"rendered":"How can a young blue giant have a white dwarf companion star?"},"content":{"rendered":"<p>\t\t\tBack to Article List\t\t<\/p>\n<p>\n\t\t\t\tBorn at the same time, the star that formed Sirius B started out more massive and evolved more quickly than its companion, Sirius A.\t\t\t<\/p>\n<p>\t\t\t\t\tBy\t\t\t\t\t<a href=\"https:\/\/www.astronomy.com\/author\/astronomystaff\/\" title=\"Posts by Astronomy Staff\" class=\"author url fn\" rel=\"author nofollow noopener\" target=\"_blank\">Astronomy Staff<\/a><br \/>\n\t\t\t\t | <\/p>\n<p>\t\t\t\t\tPublished: May 21, 2026<br \/>\n\t\t\t\t| Last updated on May 22, 2026\t\t\t<\/p>\n<p><\/p>\n<p>\t\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"2560\" height=\"1920\" src=\"https:\/\/www.europesays.com\/ie\/wp-content\/uploads\/2026\/05\/ASY-SK0726_02.jpg\" class=\"attachment-large size-large wp-post-image\" alt=\"An artist's illustration of two stars against a dense, starry background with red and blue nebula clouds. A large, intensely bright white star dominates the left side of the image, while a smaller, vivid blue star glows to its right, suggesting a binary star system.\"\/><\/p>\n<p>\n\t\t\t\t\t\tThe stars of the Sirius binary star system are about the same age, around 250 million years old. But because Sirius B (to the right in this artist\u2019s impression) was originally more massive, it\u2019s now further along in its stellar evolution. Credit: NASA, ESA and G. Bacon (STScI)\t\t\t\t\t<\/p>\n<p class=\"wp-block-paragraph\"><strong>Sirius is a blue giant, which burns through its fuel quickly and lives only a relatively short period of time. Yet it has a white dwarf companion (Sirius B) and white dwarfs are the end result of stars like our Sun, which live for billions of years. How can a young blue giant have a companion star that\u2019s billions of years older?<\/strong><strong><\/strong><\/p>\n<p><strong>John Gould<\/strong><br \/>Moab, Utah<\/p>\n<p class=\"wp-block-paragraph\">This is a great question. It hinges on the fact that while we often say that white dwarfs are the remnants of Sun-like stars, the term Sun-like in this case is admittedly a bit of an oversimplification.<\/p>\n<p>PREMIUM CONTENT<\/p>\n<p>\t\t\t\t\t\t\tA Subscription To Astronomy Magazine Is Required To Continue Reading<\/p>\n<p class=\"kserv-gate__simple-message\">Already a subscriber? Log in to continue reading or subscribe today to get full access to all content.<\/p>\n<p>\t\t\t\tContinue Reading<\/p>\n<p>PREMIUM CONTENT<\/p>\n<p>\t\t\t\t\t\t\tA Subscription To Astronomy Magazine Is Required To Continue Reading<\/p>\n<p class=\"kserv-gate__simple-message\">Already a subscriber? Log in to continue reading or subscribe today to get full access to all content.<\/p>\n","protected":false},"excerpt":{"rendered":"Back to Article List Born at the same time, the star that formed Sirius B started out more&hellip;\n","protected":false},"author":2,"featured_media":498821,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":"","_share_on_mastodon":"0"},"categories":[270],"tags":[93765,18,19,17,361,133,451,1240],"class_list":["post-498820","post","type-post","status-publish","format-standard","has-post-thumbnail","category-space","tag-ask-astro","tag-eire","tag-ie","tag-ireland","tag-magazine","tag-science","tag-space","tag-stars"],"share_on_mastodon":{"url":"https:\/\/pubeurope.com\/@ie\/116623117007582736","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts\/498820","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/comments?post=498820"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts\/498820\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/media\/498821"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/media?parent=498820"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/categories?post=498820"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/tags?post=498820"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}