{"id":16830,"date":"2018-10-03T18:27:07","date_gmt":"2018-10-03T22:27:07","guid":{"rendered":"http:\/\/hobbyspace.com\/Blog\/?p=16830"},"modified":"2018-10-03T18:27:07","modified_gmt":"2018-10-03T22:27:07","slug":"hubble-observations-indicate-a-neptune-sized-moon-orbiting-jupiter-sized-exoplanet","status":"publish","type":"post","link":"https:\/\/hobbyspace.com\/Blog\/?p=16830","title":{"rendered":"Hubble: Observations indicate a Neptune-sized moon orbiting Jupiter-sized exoplanet"},"content":{"rendered":"<p>Researchers using the Hubble telescope appear to have observed a gas-giant sized Moon orbiting an even larger planet in another star system:<\/p>\n<p style=\"text-align: center;\"><a href=\"https:\/\/www.spacetelescope.org\/news\/heic1817\/?lang\" target=\"_blank\" rel=\"noopener\"><strong>Hubble finds compelling evidence for a moon outside the Solar System<\/strong><\/a><br \/>\n<em>Neptune-sized moon orbits Jupiter-sized planet<\/em><\/p>\n<p><figure id=\"attachment_16831\" aria-describedby=\"caption-attachment-16831\" style=\"width: 500px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/www.spacetelescope.org\/images\/heic1817a\/\" target=\"_blank\" rel=\"noopener\"><img loading=\"lazy\" decoding=\"async\" data-attachment-id=\"16831\" data-permalink=\"https:\/\/hobbyspace.com\/Blog\/?attachment_id=16831\" data-orig-file=\"https:\/\/hobbyspace.com\/Blog\/wp-content\/uploads\/2018\/10\/heic1817a1.jpg\" data-orig-size=\"700,420\" data-comments-opened=\"0\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;NASA, ESA&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;This artist\\u2019s impression depicts the exomoon candidate Kepler-1625b-i, the planet it is orbiting and the star in the centre of the star system. Kepler-1625b-i is the first exomoon candidate and, if confirmed, the first moon to be found outside the Solar System. Like many exoplanets, Kepler-1625b-i was discovered using the transit method. Exomoons are difficult to find because they are smaller than their companion planets, so their transit signal is weak, and their position in the system changes with each transit because of their orbit. This requires extensive modelling and data analysis.&quot;,&quot;created_timestamp&quot;:&quot;1538596800&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;Exomoon orbiting its planet (artist\\u2019s impression)&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"Exomoon orbiting its planet (artist\u2019s impression)\" data-image-description=\"\" data-image-caption=\"&lt;p&gt;This artist\u2019s impression depicts the exomoon candidate Kepler-1625b-i, the planet it is orbiting and the star in the centre of the star system. Kepler-1625b-i is the first exomoon candidate and, if confirmed, the first moon to be found outside the Solar System. Like many exoplanets, Kepler-1625b-i was discovered using the transit method. Exomoons are difficult to find because they are smaller than their companion planets, so their transit signal is weak, and their position in the system changes with each transit because of their orbit. This requires extensive modelling and data analysis.&lt;\/p&gt;\n\" data-large-file=\"https:\/\/hobbyspace.com\/Blog\/wp-content\/uploads\/2018\/10\/heic1817a1.jpg\" class=\"wp-image-16831\" src=\"http:\/\/hobbyspace.com\/Blog\/wp-content\/uploads\/2018\/10\/heic1817a1.jpg\" alt=\"\" width=\"500\" height=\"300\" srcset=\"https:\/\/hobbyspace.com\/Blog\/wp-content\/uploads\/2018\/10\/heic1817a1.jpg 700w, https:\/\/hobbyspace.com\/Blog\/wp-content\/uploads\/2018\/10\/heic1817a1-300x180.jpg 300w\" sizes=\"auto, (max-width: 500px) 100vw, 500px\" \/><\/a><figcaption id=\"caption-attachment-16831\" class=\"wp-caption-text\"><em>This artist\u2019s impression depicts the exomoon candidate Kepler-1625b-i, the planet it is orbiting and the star in the centre of the star system. Kepler-1625b-i is the first exomoon candidate and, if confirmed, the first moon to be found outside the Solar System. Like many exoplanets, Kepler-1625b-i was discovered using the transit method. Exomoons are difficult to find because they are smaller than their companion planets, so their transit signal is weak, and their position in the system changes with each transit because of their orbit. This requires extensive modelling and data analysis. [<a href=\"https:\/\/www.spacetelescope.org\/images\/heic1817a\/\" target=\"_blank\" rel=\"noopener\">Higher-res images<\/a>]<br \/><\/em><\/figcaption><\/figure>Using the NASA\/ESA Hubble Space Telescope and older data from the Kepler Space Telescope two astronomers have found the first compelling evidence for a moon outside our own Solar System. The data indicate an exomoon the size of Neptune, in a stellar system 8000 light-years from Earth. The new results are presented in the journal Science Advances.<\/p>\n<p>The hunt for <a href=\"https:\/\/en.wikipedia.org\/wiki\/Exoplanet\" target=\"_blank\" rel=\"noopener\">exoplanets<\/a> \u2014 planets outside our own Solar System \u2014 provided its first results only 30 years ago. While astronomers now find these planets on a regular basis, the search for moons orbiting exoplanets wasn\u2019t successful \u2014 until today.<\/p>\n<p><span class=\"embed-youtube\" style=\"text-align:center; display: block;\"><iframe loading=\"lazy\" class=\"youtube-player\" width=\"1600\" height=\"900\" src=\"https:\/\/www.youtube.com\/embed\/dduClMGMU-U?version=3&#038;rel=1&#038;showsearch=0&#038;showinfo=1&#038;iv_load_policy=1&#038;fs=1&#038;hl=en&#038;autohide=2&#038;wmode=transparent\" allowfullscreen=\"true\" style=\"border:0;\" sandbox=\"allow-scripts allow-same-origin allow-popups allow-presentation allow-popups-to-escape-sandbox\"><\/iframe><\/span><\/p>\n<p style=\"padding-left: 60px;\"><em>This animation demonstrates how the measured light curve from the star Kepler-1625b led to the conclusion that the system may consist of not only a planet, but also at least one moon.<\/em><\/p>\n<p style=\"padding-left: 60px;\"><em>When the planet moves in front of its parent star a tiny portion of its light is blocked by the disc of the planet, so we observe a dimming of the light from the star. Right after the exoplanet has finished its transit the starlight is seen to dim slightly again, suggesting the presence of a moon trailing the planet. Credit: ESA\/Hubble, L. Cal\u00e7ada<\/em><\/p>\n<p>In 2017 <a href=\"https:\/\/www.nasa.gov\/mission_pages\/kepler\/main\/index.html\" target=\"_blank\" rel=\"noopener\">NASA\u2019s Kepler Space Telescope<\/a> detected hints of an exomoon orbiting the planet <a href=\"https:\/\/en.wikipedia.org\/wiki\/Kepler-1625b\" target=\"_blank\" rel=\"noopener\">Kepler-1625b<\/a>. Now, two scientists from Columbia University in New York (USA) have used the incomparable capabilities of the <a href=\"https:\/\/www.spacetelescope.org\/\" target=\"_blank\" rel=\"noopener\">NASA\/ESA Hubble Space Telescope<\/a> to study the star <a href=\"https:\/\/en.wikipedia.org\/wiki\/Kepler-1625\" target=\"_blank\" rel=\"noopener\">Kepler-1625<\/a>, 8000 light-years away, and its planet in more detail. The new observations made with Hubble show compelling evidence for a large exomoon orbiting the only known planet of Kepler-1625. If confirmed, this would be the first discovery of a moon outside our Solar System.<\/p>\n<p>The candidate moon, with the designation Kepler-1625b-i, is unusual because of its large size; it is comparable in diameter to the planet <a href=\"https:\/\/en.wikipedia.org\/wiki\/Neptune\" target=\"_blank\" rel=\"noopener\">Neptune<\/a>. Such gargantuan moons are unknown in our own Solar System.<\/p>\n<p style=\"padding-left: 30px;\"><em>\u201cThis may yield new insights into the development of planetary systems and may cause astronomers to revisit theories of how moons form,\u201d<\/em><\/p>\n<p>Alex Teachey, a graduate student who led the study, explained excitedly <a href=\"#1\">[1]<\/a>.<\/p>\n<p>Like its moon, Kepler-1625b is also bigger than its counterparts in the Solar System. The exoplanet is a gas giant, several times more massive than Jupiter <a href=\"#2\">[2]<\/a>. It orbits its parent star at a distance similar to the distance between the Sun and Earth, which puts it \u2014 and its candidate moon \u2014 at the inner edge of the habitable zone of the star system <a href=\"#3\">[3]<\/a>.<\/p>\n<p>To find evidence for the existence of the exomoon, the team observed the planet while it was in <a href=\"https:\/\/en.wikipedia.org\/wiki\/Methods_of_detecting_exoplanets#Transit_photometry\" target=\"_blank\" rel=\"noopener\">transit<\/a> in front of its parent star, causing a dimming of the starlight.<\/p>\n<p style=\"padding-left: 30px;\"><em>\u201cWe saw little deviations and wobbles in the light curve that caught our attention,\u201d<\/em><\/p>\n<p>David Kipping, second author of the study, said.<\/p>\n<p>The planet was observed by Hubble before and during its 19-hour-long transit. After the transit ended, Hubble detected a second and much smaller decrease in the star\u2019s brightness approximately 3.5 hours later, consistent with the effect of a moon trailing the planet.<\/p>\n<p style=\"padding-left: 30px;\"><em>\u201cIt was definitely a shocking moment to see that light curve \u2014 my heart started beating a little faster and I just kept looking at that signature,\u201d<\/em><\/p>\n<p>David Kipping described his feelings. Unfortunately, the scheduled Hubble observations ended before the complete transit of the moon could be captured.<\/p>\n<p>In addition to this second dip in the light curve, Hubble provided compelling supporting evidence for the moon hypothesis by detecting the planet\u2019s transit more than an hour earlier than predicted. This is consistent with a model of the system in which the planet and its moon orbit a common centre of gravity, causing the planet to wobble away from its predicted location <a href=\"#4\">[4]<\/a>.<\/p>\n<p>In principle this anomaly could also be caused by the gravitational pull of a hypothetical second planet in the system, but the Kepler Space Telescope found no evidence for additional planets around the star during its four year mission. Still, further observations by Hubble are needed to fully confirm the existence of Kepler-1625b-i.<\/p>\n<p style=\"padding-left: 30px;\"><em>\u201cIf confirmed, Kepler-1625b-i will certainly provide an interesting puzzle for theorists to solve,\u201d<\/em> said Kipping. Teachey concluded: <em>\u201cIt is an exciting reminder of how little we really know about distant planetary systems and the great spirit of discovery exoplanetary science embodies.\u201d<\/em><\/p>\n<h3>Notes<\/h3>\n<p><a class=\"anchor\" name=\"1\"><\/a>[1] The moons of Jupiter and Saturn likely formed through the agglomeration into a disc of material orbiting the planets, so it is possible that this exomoon also formed in a circumplanetary disc. Another possibility is that a passing object was captured by the planet\u2019s gravity. Tidal forces between the two objects would rob momentum from the less massive companion and eventually pull it into a permanent orbit. There are no indications of tidal capture among our Solar System\u2019s moons. In the case of the Earth\u2013Moon system, an early collision with a larger body is hypothesised to have blasted off material that later coalesced into a moon. However, Kepler-1625b and its candidate moon are gaseous, not rocky, so such a collision would not have led to the condensation of a satellite.<\/p>\n<p><a class=\"anchor\" name=\"2\"><\/a>[2] Despite its size, the mass of the candidate moon is estimated to be only 1.5 percent of the mass of its companion planet. This value is close to the mass ratio between Earth and the Moon.<\/p>\n<p><a class=\"anchor\" name=\"3\"><\/a>[3] While both the planet and its candidate moon are within the habitable zone, where moderate temperatures allow for the existence of liquid water, both bodies are considered to be gaseous and therefore unsuitable for life as we know it.<\/p>\n<p><a class=\"anchor\" name=\"4\"><\/a>[4] A distant observer watching the Earth and Moon transit the Sun would note similar anomalies in the timing of Earth\u2019s transit.<\/p>\n<p><strong>More information<\/strong><\/p>\n<p>The Hubble Space Telescope is a project of international cooperation between ESA and NASA.<\/p>\n<p>The results were presented in the paper Evidence for a large exomoon orbiting Kepler-1625b in the journal Science Advances.<\/p>\n<p>The team of astronomers in this study consists of Alex Teachey and David M. Kipping (Columbia University, New York, USA).<\/p>\n<p>Image credit: NASA, ESA<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Researchers using the Hubble telescope appear to have observed a gas-giant sized Moon orbiting an even larger planet in another star system: Hubble finds compelling evidence for a moon outside the Solar System Neptune-sized moon orbits Jupiter-sized planet Using the NASA\/ESA Hubble Space Telescope and older data from the Kepler Space Telescope two astronomers have &hellip; <a href=\"https:\/\/hobbyspace.com\/Blog\/?p=16830\" class=\"more-link\">Continue reading <span class=\"screen-reader-text\">Hubble: Observations indicate a Neptune-sized moon orbiting Jupiter-sized exoplanet<\/span> <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[12,46],"tags":[],"class_list":["post-16830","post","type-post","status-publish","format-standard","hentry","category-astronomy","category-exoplanets"],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p34aWK-4ns","jetpack-related-posts":[{"id":9794,"url":"https:\/\/hobbyspace.com\/Blog\/?p=9794","url_meta":{"origin":16830,"position":0},"title":"Review: &#8220;Five Billion Years of Solitude&#8221; by Lee Billings","author":"TopSpacer","date":"January 29, 2015","format":false,"excerpt":"Zooming in on the universe has\u00a0not been easy or quick. 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