{"id":81373,"date":"2018-06-27T07:00:01","date_gmt":"2018-06-27T17:00:01","guid":{"rendered":"https:\/\/www.hawaii.edu\/news\/?p=81373"},"modified":"2019-03-29T13:12:57","modified_gmt":"2019-03-29T23:12:57","slug":"interstellar-asteroid-comet","status":"publish","type":"post","link":"https:\/\/www.hawaii.edu\/news\/2018\/06\/27\/interstellar-asteroid-comet\/","title":{"rendered":"Is the interstellar asteroid really a comet?"},"content":{"rendered":"Reading time: <\/span> 2<\/span> minutes<\/span><\/span>
\"Artist\u2019s
This artist\u2019s impression shows the first interstellar object discovered in the Solar System, ʻOumuamua. Observations made with the NASA\/ESA<\/abbr> Hubble Space Telescope and others show that the object is moving faster than predicted while leaving the Solar System. Researchers assume that venting material from its surface due to solar heating is responsible for this behavior. This outgassing can be seen in this artist\u2019s impression as a subtle cloud being ejected from the side of the object facing the Sun. As outgassing is a behavior typical for comets, the team thinks that ʻOumuamua\u2019s previous classification as an interstellar asteroid has to be corrected. Credit: ESA<\/abbr>\/Hubble, NASA, ESO<\/abbr>, M. Kornmesser<\/figcaption><\/figure>\n

The interstellar object ʻOumuamua was discovered back on October 19, 2017, but the puzzle of its true nature has taken months to unravel, and may never be fully solved.<\/p>\n

Meaning ‘scout from the distant past’ in Hawaiian, ʻOumuamua was found by astronomers working with the University of Â鶹´«Ã½<\/span>‘s Pan-STARRS1<\/a> survey as it came close to Earth’s orbit. But what is it—an asteroid, or a comet? As soon as it was spotted, astronomers from around the world were on the case.<\/p>\n

The first clue: its trajectory. Extensive follow-up observations by the Canada-France-Â鶹´«Ã½<\/span> Telescope<\/a>, the European Space Agency’s Optical Ground Station telescope in Tenerife, Canary Islands and other telescopes around the world have helped pin it down.<\/p>\n

ʻOumuamua was first spotted about a month after its closest approach to the Sun, which took it within the orbit of Mercury. Unlike any asteroid or comet observed before, this new object sped past the Sun, approaching from ‘above’ the plane of the planets on a highly inclined orbit, moving fast enough (70,800 miles per hour as of July 1, 2018) to escape the Sun’s gravitational pull and eventually depart our Solar System.<\/p>\n

Initially, astronomers assumed ʻOumuamua was a comet. Current understanding of planet formation predicts more interstellar comets than interstellar asteroids. However, astronomers did not see evidence of gas emission or a dusty environment in the observations. Without these hallmarks of cometary activity, it was classified as the first interstellar asteroid.<\/p>\n

A team of astronomers led by Marco Micheli of ESA<\/abbr>‘s SSA-NEO<\/abbr> Coordination Centre, and Karen Meech<\/strong><\/a> of the UH<\/abbr> Institute for Astronomy<\/a>, continued to make high precision measurements of the object and its position.<\/p>\n

The story has another surprising twist. Learn more at the Institute for Astronomy website<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"

Researchers say ʻOumuamua’s previous classification as an interstellar asteroid has to be corrected and should be changed to a comet.<\/p>\n","protected":false},"author":16,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[30],"tags":[34,35,9],"class_list":["post-81373","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-research","tag-astronomy","tag-institute-for-astronomy","tag-uh-manoa","entry","has-media"],"aioseo_notices":[],"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/www.hawaii.edu\/news\/wp-json\/wp\/v2\/posts\/81373","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=81373"}],"version-history":[{"count":13,"href":"https:\/\/www.hawaii.edu\/news\/wp-json\/wp\/v2\/posts\/81373\/revisions"}],"predecessor-version":[{"id":81434,"href":"https:\/\/www.hawaii.edu\/news\/wp-json\/wp\/v2\/posts\/81373\/revisions\/81434"}],"wp:attachment":[{"href":"https:\/\/www.hawaii.edu\/news\/wp-json\/wp\/v2\/media?parent=81373"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.hawaii.edu\/news\/wp-json\/wp\/v2\/categories?post=81373"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.hawaii.edu\/news\/wp-json\/wp\/v2\/tags?post=81373"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}