{"id":61123,"date":"2017-06-05T09:34:11","date_gmt":"2017-06-05T19:34:11","guid":{"rendered":"http:\/\/www.hawaii.edu\/news\/?p=61123"},"modified":"2020-03-21T14:35:15","modified_gmt":"2020-03-22T00:35:15","slug":"separating-true-stars-from-wannabes","status":"publish","type":"post","link":"https:\/\/www.hawaii.edu\/news\/2017\/06\/05\/separating-true-stars-from-wannabes\/","title":{"rendered":"Separating true stars from wannabes"},"content":{"rendered":"<span class=\"span-reading-time rt-reading-time\" style=\"display: block;\"><span class=\"rt-label rt-prefix\">Reading time: <\/span> <span class=\"rt-time\"> 2<\/span> <span class=\"rt-label rt-postfix\">minutes<\/span><\/span><div class=\"responsive-video-wrap\"><iframe loading=\"lazy\" title=\"Youtube video player\" width=\"620\" height=\"349\" src=\"https:\/\/www.youtube.com\/embed\/wa4iNrb8USA?showinfo=0\" allowfullscreen><\/iframe><\/div>\n<p class=\"clear-photo\">Astronomers have shown what separates real stars from the wannabes. Not in Hollywood, but out in the universe.<\/p>\n<p>&ldquo;When we look up and see the stars shining at night, we are seeing only part of the story,&rdquo; said <strong>Trent Dupuy<\/strong> of the University of Texas at Austin and a graduate of the <a href=\"http:\/\/www.ifa.hawaii.edu\/\">Institute for Astronomy<\/a> at the University of <span aria-label=\"Hawaii\">Â鶹´«Ã½<\/span> at M\u0101noa. &ldquo;Not everything that could be a star &lsquo;makes it,&rsquo; and figuring out why this process sometimes fails is just as important as understanding when it succeeds.&rdquo;<\/p>\n<p>Dupuy is the lead author of the study and presented his research June 5 in a news conference at the semi-annual meeting of the American Astronomical Society in Austin. The research will be published in <em>The Astrophysical Journal Supplement<\/em>, and <a href=\"http:\/\/arxiv.org\/abs\/1703.05775\">a preprint can be found online<\/a>.<\/p>\n<p>Stars form when a cloud of gas and dust collapses due to gravity, and the resulting ball of matter becomes hot enough and dense enough to sustain nuclear fusion at its core. Fusion produces huge amounts of energy&#8212;it&#8217;s what makes stars shine. In the Sun&#8217;s case, it&#8217;s what makes most life on Earth possible.\u00a0<\/p>\n<p>But not all collapsing gas clouds are created equal. Sometimes, the collapsing cloud makes a ball that isn&#8217;t dense enough to ignite fusion. These &lsquo;failed stars&rsquo; are known as brown dwarfs.<\/p>\n<p>This simple division between stars and brown dwarfs has been used for a long time. Astronomers have had theories about how massive the collapsing ball has to be in order to form a star (or not) for over 50 years. However, the dividing line in mass has never been confirmed by experiment.<\/p>\n<p>Now, Dupuy and <abbr title=\"Institute for Astronomy\">IfA<\/abbr> Astronomer <a href=\"http:\/\/www.ifa.hawaii.edu\/~mliu\/\"><strong>Michael Liu<\/strong><\/a> have done just that. They found that an object must weigh at least 70 Jupiters in order to start hydrogen fusion. If it weighs less, the star does not ignite and becomes a brown dwarf instead.<\/p>\n<p>How did they reach that conclusion? For a decade, the two studied 31 faint brown dwarf binaries (pairs of these objects that orbit each other) using two powerful telescopes in <span aria-label=\"Hawaii\">Â鶹´«Ã½<\/span>&#8212;the <a href=\"http:\/\/www.keckobservatory.org\/\">W. M. Keck Observatory<\/a> and <a href=\"http:\/\/www.cfht.hawaii.edu\/\">Canada-France-<span aria-label=\"Hawaii\">Â鶹´«Ã½<\/span> telescopes<\/a>&#8217;as well as data from the <a href=\"http:\/\/hubblesite.org\/\">Hubble Space Telescope<\/a>.<\/p>\n<p>Read more at the <a href=\"http:\/\/www.ifa.hawaii.edu\/info\/press-releases\/bdmasslimit\/\">Institute for Astronomy news release<\/a>.<\/p>\n<p><em>&#8212;By Roy Gal<\/em><\/p>\n<figure id=\"attachment_61126\" aria-describedby=\"caption-attachment-61126\" style=\"width: 630px\" class=\"wp-caption alignright\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/www.hawaii.edu\/news\/wp-content\/uploads\/2017\/06\/manoa-ifa-true-stars.jpg\" alt=\"Map of the night sky with binaries\" width=\"620\" height=\"349\" class=\"size-full wp-image-61126\" srcset=\"https:\/\/www.hawaii.edu\/news\/wp-content\/uploads\/2017\/06\/manoa-ifa-true-stars.jpg 620w, https:\/\/www.hawaii.edu\/news\/wp-content\/uploads\/2017\/06\/manoa-ifa-true-stars-260x146.jpg 260w\" sizes=\"auto, (max-width: 620px) 100vw, 620px\" \/><figcaption id=\"caption-attachment-61126\" class=\"wp-caption-text\">Several of the binaries from the study, each orbiting around its center of mass, which is marked by an x. Credit: Trent Dupuy, Karen Teramura, PS1SC<\/figcaption><\/figure>\n","protected":false},"excerpt":{"rendered":"<p>Institute for Astronomy researchers discover the dividing line of mass that separates stars from brown dwarfs.<\/p>\n","protected":false},"author":16,"featured_media":61126,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[30],"tags":[34,35,9,56],"class_list":["post-61123","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-research","tag-astronomy","tag-institute-for-astronomy","tag-uh-manoa","tag-video-2","entry","has-media"],"aioseo_notices":[],"jetpack_featured_media_url":"https:\/\/www.hawaii.edu\/news\/wp-content\/uploads\/2017\/06\/manoa-ifa-true-stars.jpg","_links":{"self":[{"href":"https:\/\/www.hawaii.edu\/news\/wp-json\/wp\/v2\/posts\/61123","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.hawaii.edu\/news\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.hawaii.edu\/news\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.hawaii.edu\/news\/wp-json\/wp\/v2\/users\/16"}],"replies":[{"embeddable":true,"href":"https:\/\/www.hawaii.edu\/news\/wp-json\/wp\/v2\/comments?post=61123"}],"version-history":[{"count":9,"href":"https:\/\/www.hawaii.edu\/news\/wp-json\/wp\/v2\/posts\/61123\/revisions"}],"predecessor-version":[{"id":109971,"href":"https:\/\/www.hawaii.edu\/news\/wp-json\/wp\/v2\/posts\/61123\/revisions\/109971"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.hawaii.edu\/news\/wp-json\/wp\/v2\/media\/61126"}],"wp:attachment":[{"href":"https:\/\/www.hawaii.edu\/news\/wp-json\/wp\/v2\/media?parent=61123"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.hawaii.edu\/news\/wp-json\/wp\/v2\/categories?post=61123"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.hawaii.edu\/news\/wp-json\/wp\/v2\/tags?post=61123"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}