{"id":12764,"date":"2021-09-03T00:00:00","date_gmt":"2021-09-03T00:00:00","guid":{"rendered":"https:\/\/www.nextias.com\/current_affairs\/uncategorized\/03-09-2021\/blue-straggler\/"},"modified":"2021-09-03T00:00:00","modified_gmt":"2021-09-03T00:00:00","slug":"blue-straggler","status":"publish","type":"post","link":"https:\/\/www.nextias.com\/ca\/current-affairs\/03-09-2021\/blue-straggler","title":{"rendered":"Blue Straggler"},"content":{"rendered":"<p><span style=\"font-size:13pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\"><strong><u>In News\u00a0<\/u><\/strong><\/span><\/span><\/span><\/p>\n<ul>\n<li style=\"list-style-type:disc\"><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\">Recently, Indian researchers found that <\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\"><strong>half of the blue stragglers<\/strong><\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\"> in their sample are formed through <\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\"><strong>mass transfer from a close binary companion star<\/strong><\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\">.<\/span><\/span><\/span><\/li>\n<li style=\"list-style-type:disc\"><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\">One third are likely formed through <\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\"><strong>collisions of 2 stars<\/strong><\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\">, and the remaining are formed through <\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\"><strong>interactions of more than 2 stars<\/strong><\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\">.<\/span><\/span><\/span><\/li>\n<li style=\"list-style-type:disc\"><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\">This was the first-ever comprehensive analysis of blue stragglers.<\/span><\/span><\/span><\/li>\n<\/ul>\n<p><span style=\"font-size:13pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\"><strong><u>About Blue straggler<\/u><\/strong><\/span><\/span><\/span><span style=\"font-size:13pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\"><strong><u> <\/u><\/strong><\/span><\/span><\/span><\/p>\n<ul>\n<li style=\"list-style-type:disc\"><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\">Blue stragglers are a class of <\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\"><strong>stars on open or globular clusters<\/strong><\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\"> that stand out as <\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\"><strong>they are bigger and bluer <\/strong><\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\">than the<\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\"><strong> rest of the stars<\/strong><\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\">.<\/span><\/span><\/span>\n<ul>\n<li style=\"list-style-type:circle\"><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\">They have intrigued scientists who have for long probed their origin.<\/span><\/span><\/span><\/li>\n<\/ul>\n<\/li>\n<li style=\"list-style-type:disc\"><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\">It is found in <\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\"><strong>old star clusters and appears<\/strong><\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\"> to be <\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\"><strong>lagging behind most of the other stars <\/strong><\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\">in the cluster in its evolution toward a cooler, reddish state.\u00a0<\/span><\/span><\/span>\n<ul>\n<li style=\"list-style-type:circle\"><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\">Blue stragglers tend to be strongly concentrated toward the centre of the cluster.\u00a0<\/span><\/span><\/span><\/li>\n<\/ul>\n<\/li>\n<li style=\"list-style-type:disc\"><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\"><strong>Formation<\/strong><\/span><\/span><\/span>\n<ul>\n<li style=\"list-style-type:circle\"><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\">A bunch of stars born at the same time from the same cloud form a star cluster.<\/span><\/span><\/span><\/li>\n<li style=\"list-style-type:circle\"><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\">As time passes, <\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\"><strong>each star evolves<\/strong><\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\"> differently depending on its mass.\u00a0<\/span><\/span><\/span><\/li>\n<li style=\"list-style-type:circle\"><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\">The most massive and bright stars evolve and move off the main sequence creating a bend in their track, known as the turnoff.\u00a0<\/span><\/span><\/span><\/li>\n<li style=\"list-style-type:circle\"><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\">Stars above this<\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\"><strong> bend or brighter and hotter stars<\/strong><\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\"> are not expected in a cluster, as they leave the main sequence to become red giants.\u00a0<\/span><\/span><\/span><\/li>\n<li style=\"list-style-type:circle\"><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\">But in 1953, Allan Sandage found that some stars seem to be hotter than the <\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\"><strong>turnoff of the parent cluster.\u00a0<\/strong><\/span><\/span><\/span><\/li>\n<li style=\"list-style-type:circle\"><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\">Initially, these blue stars still straggling above the turnoff were not part of these clusters.\u00a0<\/span><\/span><\/span><\/li>\n<li style=\"list-style-type:circle\"><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\">However, later studies confirmed that these stars are indeed cluster members, and they were termed \u201c<\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\"><strong>Blue Stragglers\u201d.\u00a0<\/strong><\/span><\/span><\/span><\/li>\n<\/ul>\n<\/li>\n<li style=\"list-style-type:disc\"><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\"><strong>Study\u00a0<\/strong><\/span><\/span><\/span>\n<ul>\n<li style=\"list-style-type:circle\"><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\">Researchers utilised the <\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\"><strong>Gaia telescope <\/strong><\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\">with its <\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\"><strong>excellent positional accuracy<\/strong><\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\"> to select the <\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\"><strong>blue stragglers <\/strong><\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\">in <\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\"><strong>clusters and understand<\/strong><\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\"> how many such stars there are, where they are and how they are formed.<\/span><\/span><\/span><\/li>\n<li style=\"list-style-type:circle\"><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\">They found that among the clusters they scanned,<\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\"><strong> 228 have a total of 868 blue stragglers.\u00a0<\/strong><\/span><\/span><\/span><\/li>\n<li style=\"list-style-type:circle\"><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\">This first-ever comprehensive analysis of blue stragglers has been published in the journal Monthly Notices of the Royal Astronomical Society.\u00a0<\/span><\/span><\/span><\/li>\n<li style=\"list-style-type:circle\"><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\">It showed that these stars are primarily <\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\"><strong>present in the older and massive<\/strong><\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\"> star clusters. And due to their large mass, they are <\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\"><strong>segregated towards the centre of the clusters.<\/strong><\/span><\/span><\/span><\/li>\n<li style=\"list-style-type:circle\"><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\">\u00a0The researchers compared the <\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\"><strong>mass of the blue stragglers<\/strong><\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\"> to the mass of the turnoff stars (which are the most massive \u2018normal\u2019 stars in the cluster) and predicted the <\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\"><strong>formation mechanisms.<\/strong><\/span><\/span><\/span><\/li>\n<li style=\"list-style-type:circle\"><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\">Overall, they found that <\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\"><strong>more than 54% of blue stragglers<\/strong><\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\"> are formed <\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\"><strong>through mass transfer <\/strong><\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\">from a<\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\"><strong> close binary companion star,<\/strong><\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\"> and <\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\"><strong>30% of the blue stragglers<\/strong><\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\"> are likely formed through collisions of 2 stars.<\/span><\/span><\/span>\n<ul>\n<li style=\"list-style-type:square\"><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\">Interestingly, <\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\"><strong>10-16%<\/strong><\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\"> of the blue stragglers are formed through interactions of more than 2 stars.<\/span><\/span><\/span><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\"><strong><u>Relevance of the study\u00a0<\/u><\/strong><\/span><\/span><\/span><\/p>\n<ul>\n<li style=\"list-style-type:disc\"><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\">The study will help improve understanding of these<\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\"><strong> stellar system<\/strong><\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\">s to uncover exciting <\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\"><strong>results in studies of large stellar populations<\/strong><\/span><\/span><\/span><span style=\"font-size:12pt\"><span style=\"font-family:'Book Antiqua',serif\"><span style=\"color:#000000\">, including galaxies.<\/span><\/span><\/span><\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>In News\u00a0 Recently, Indian researchers found that half of the blue stragglers in their sample are formed through mass transfer from a close binary companion star. One third are likely formed through collisions of 2 stars, and the remaining are formed through interactions of more than 2 stars. This was the first-ever comprehensive analysis of [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":12765,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[21],"tags":[26,43],"class_list":["post-12764","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-current-affairs","tag-gs-3","tag-space"],"acf":[],"jetpack_featured_media_url":"https:\/\/wp-images.nextias.com\/cdn-cgi\/image\/format=auto\/ca\/uploads\/2023\/07\/2227759Screenshot.png","_links":{"self":[{"href":"https:\/\/www.nextias.com\/ca\/wp-json\/wp\/v2\/posts\/12764","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.nextias.com\/ca\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.nextias.com\/ca\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.nextias.com\/ca\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.nextias.com\/ca\/wp-json\/wp\/v2\/comments?post=12764"}],"version-history":[{"count":0,"href":"https:\/\/www.nextias.com\/ca\/wp-json\/wp\/v2\/posts\/12764\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.nextias.com\/ca\/wp-json\/wp\/v2\/media\/12765"}],"wp:attachment":[{"href":"https:\/\/www.nextias.com\/ca\/wp-json\/wp\/v2\/media?parent=12764"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.nextias.com\/ca\/wp-json\/wp\/v2\/categories?post=12764"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.nextias.com\/ca\/wp-json\/wp\/v2\/tags?post=12764"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}