{"id":83892,"date":"2020-04-28T19:13:28","date_gmt":"2020-04-28T18:13:28","guid":{"rendered":"http:\/\/www.astb.se\/cassiopeiabloggen\/?p=83892"},"modified":"2020-04-28T19:17:28","modified_gmt":"2020-04-28T18:17:28","slug":"nr-35-220","status":"publish","type":"post","link":"https:\/\/www.astb.se\/cassiopeiabloggen\/2020\/04\/28\/nr-35-220\/","title":{"rendered":"Nr 35 220"},"content":{"rendered":"\n<h2 class=\"wp-block-heading\">ATLAS-kometen pulveriseras inf\u00f6r Hubbles rymd\u00f6ga<\/h2>\n\n\n\n<p>Senaste nytt <a href=\"http:\/\/The NASA\/ESA Hubble Space Telescope has provided astronomers with the sharpest view yet of the breakup of Comet C\/2019 Y4 (ATLAS). The telescope resolved roughly 30 fragments of the fragile comet on 20 April and 25 pieces on 23 April. The comet was first discovered in December 2019 by the ATLAS (Asteroid Terrestrial-impact Last Alert System) robotic astronomical survey system in Hawai\u02bbi, USA. It brightened quickly until mid-March, and some astronomers initially anticipated that it might be visible to the naked eye in May to become one of the most spectacular comets seen in the last two decades. However, the comet abruptly began to get dimmer, leading astronomers to speculate that the icy core may be fragmenting, or even disintegrating. ATLAS\u2019s fragmentation was confirmed by amateur astronomer Jose de Queiroz, who photographed around three pieces of the comet on 11 April.\u00a0 The Hubble Space Telescope\u2019s new observations of the comet\u2019s breakup on 20 and 23 April reveal that the broken fragments are all enveloped in a sunlight-swept tail of cometary dust. These images provide further evidence that comet fragmentation is probably common and might even be the dominant mechanism by which the solid, icy nuclei of comets die.\u00a0 \u201cTheir appearance changes substantially between the two days, so much so that it's quite difficult to connect the dots,\u201d said David Jewitt of UCLA, leader of one of two teams who imaged the doomed comet with Hubble. \u201cI don\u2019t know whether this is because the individual pieces are flashing on and off as they reflect sunlight, acting like twinkling lights on a Christmas tree, or because different fragments appear on different days.\u201d \u201cThis is really exciting \u2014 both because such events are super cool to watch and because they do not happen very often. Most comets that fragment are too dim to see. Events at such scale only happen once or twice a decade,&quot; said the leader of the second Hubble observing team, Quanzhi Ye, of the University of Maryland. Because comet fragmentation happens quickly and unpredictably, reliable observations are rare. Therefore, astronomers remain largely uncertain about the cause of fragmentation. One suggestion is that the original nucleus spins itself into pieces because of the jet action of outgassing from sublimating ices. As this venting is likely not evenly dispersed across the comet, it enhances the breakup. \u201cFurther analysis of the Hubble data might be able to show whether or not this mechanism is responsible,\u201d said Jewitt. \u201cRegardless, it's quite special to get a look with Hubble at this dying comet.\u201d Hubble\u2019s crisp images\u00a0 may yield new clues to the breakup. The telescope has distinguished pieces as small as the size of a house. Before the breakup, the entire nucleus may have been no more than the length of two football fields. The disintegrating ATLAS comet is currently located inside the orbit of Mars, at a distance of approximately 145 million kilometres from Earth when the latest Hubble observations were taken. The comet will make its closest approach to Earth on 23 May at a distance of approximately 115 million kilometres, and eight days later it will skirt within 37 million kilometres of the Sun.\">fr\u00e5n Hubble-teleskopet f\u00e5r ni h\u00e4r<\/a> &#8211; gratis som alltid. KLICKA upp bilden p\u00e5 din sk\u00e4rm:<\/p>\n\n\n\n<p><\/p>\n\n\n<div class=\"mceTemp\"><a href=\"https:\/\/www.astb.se\/cassiopeiabloggen\/?attachment_id=83895\" rel=\"attachment wp-att-83895\"><img decoding=\"async\" class=\"size-medium wp-image-83895 aligncenter\" src=\"https:\/\/www.astb.se\/cassiopeiabloggen\/wp-content\/uploads\/2020\/04\/heic2008a2-1-300x125.jpg\" alt=\"\" width=\"300\" height=\"125\" srcset=\"https:\/\/www.astb.se\/cassiopeiabloggen\/wp-content\/uploads\/2020\/04\/heic2008a2-1-300x125.jpg 300w, https:\/\/www.astb.se\/cassiopeiabloggen\/wp-content\/uploads\/2020\/04\/heic2008a2-1-1024x427.jpg 1024w, https:\/\/www.astb.se\/cassiopeiabloggen\/wp-content\/uploads\/2020\/04\/heic2008a2-1-768x320.jpg 768w, https:\/\/www.astb.se\/cassiopeiabloggen\/wp-content\/uploads\/2020\/04\/heic2008a2-1-200x83.jpg 200w, https:\/\/www.astb.se\/cassiopeiabloggen\/wp-content\/uploads\/2020\/04\/heic2008a2-1.jpg 1280w\" sizes=\"(max-width: 300px) 100vw, 300px\" \/><\/a><\/div>\n\n<p style=\"text-align: center;\"><em>Comet C\/2019 Y4 (ATLAS) ses h\u00e4r p\u00e5 en unik serie HST-bilder: 30 fragment iakttogs 20 april, 25 den 23 april.\u00a0ATLAS \u00e4r\u00a0akronym f\u00f6r\u00a0\u00a0Asteroid Terrestrial-impact Last Alert System.<\/em><\/p>\n\n\n<p><strong>H\u00e5kan Barreg\u00e5rd<\/strong> tipsar <a href=\"https:\/\/www.popularastronomi.se\/2020\/04\/kometen-atlas-uppgang-och-fal\">om v\u00e5r egen PopAst-sajt<\/a> med diverse info.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>ATLAS-kometen pulveriseras inf\u00f6r Hubbles rymd\u00f6ga Senaste nytt fr\u00e5n Hubble-teleskopet f\u00e5r ni h\u00e4r &#8211; gratis som alltid. KLICKA upp bilden p\u00e5 din sk\u00e4rm: Comet C\/2019 Y4 (ATLAS) ses h\u00e4r p\u00e5 en unik serie HST-bilder: 30 fragment iakttogs 20 april, 25 den 23 april.\u00a0ATLAS \u00e4r\u00a0akronym f\u00f6r\u00a0\u00a0Asteroid Terrestrial-impact Last Alert System. H\u00e5kan Barreg\u00e5rd tipsar om v\u00e5r egen PopAst-sajt&hellip;&nbsp;<a href=\"https:\/\/www.astb.se\/cassiopeiabloggen\/2020\/04\/28\/nr-35-220\/\" rel=\"bookmark\">L\u00e4s mer &raquo;<span class=\"screen-reader-text\">Nr 35 220<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"rop_custom_images_group":[],"rop_custom_messages_group":[],"rop_publish_now":"initial","rop_publish_now_accounts":[],"rop_publish_now_history":[],"rop_publish_now_status":"pending","neve_meta_sidebar":"","neve_meta_container":"","neve_meta_enable_content_width":"","neve_meta_content_width":0,"neve_meta_title_alignment":"","neve_meta_author_avatar":"","neve_post_elements_order":"","neve_meta_disable_header":"","neve_meta_disable_footer":"","neve_meta_disable_title":"","footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"https:\/\/www.astb.se\/cassiopeiabloggen\/wp-json\/wp\/v2\/posts\/83892"}],"collection":[{"href":"https:\/\/www.astb.se\/cassiopeiabloggen\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.astb.se\/cassiopeiabloggen\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.astb.se\/cassiopeiabloggen\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.astb.se\/cassiopeiabloggen\/wp-json\/wp\/v2\/comments?post=83892"}],"version-history":[{"count":4,"href":"https:\/\/www.astb.se\/cassiopeiabloggen\/wp-json\/wp\/v2\/posts\/83892\/revisions"}],"predecessor-version":[{"id":83898,"href":"https:\/\/www.astb.se\/cassiopeiabloggen\/wp-json\/wp\/v2\/posts\/83892\/revisions\/83898"}],"wp:attachment":[{"href":"https:\/\/www.astb.se\/cassiopeiabloggen\/wp-json\/wp\/v2\/media?parent=83892"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.astb.se\/cassiopeiabloggen\/wp-json\/wp\/v2\/categories?post=83892"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.astb.se\/cassiopeiabloggen\/wp-json\/wp\/v2\/tags?post=83892"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}