{"id":19279,"date":"2016-08-25T01:20:56","date_gmt":"2016-08-24T17:20:56","guid":{"rendered":"https:\/\/wp-productionenv-bjg9h2g2bgg5b8aa.southeastasia-01.azurewebsites.net\/news\/proxima-centauri-b-confirmed-potentially-habitable-planet-orbits-the-star-next-door\/"},"modified":"2016-08-25T01:20:56","modified_gmt":"2016-08-24T17:20:56","slug":"proxima-centauri-b-confirmed-potentially-habitable-planet-orbits-the-star-next-door","status":"publish","type":"post","link":"https:\/\/starpath.global\/news\/proxima-centauri-b-confirmed-potentially-habitable-planet-orbits-the-star-next-door\/","title":{"rendered":"Proxima Centauri b confirmed! Potentially habitable planet orbits the star next door"},"content":{"rendered":"<figure id=\"attachment_269649\" aria-describedby=\"caption-attachment-269649\" style=\"width: 630px\" class=\"wp-caption aligncenter\"><img fetchpriority=\"high\" decoding=\"async\" class=\"size-full-width wp-image-269649\" src=\"https:\/\/cdn.geekwire.com\/wp-content\/uploads\/2016\/08\/160823-proxima-centauri-b-630x551.jpg\" alt=\"Proxima Centauri b\" width=\"630\" height=\"551\" srcset=\"https:\/\/cdn.geekwire.com\/wp-content\/uploads\/2016\/08\/160823-proxima-centauri-b-630x551.jpg 630w, https:\/\/cdn.geekwire.com\/wp-content\/uploads\/2016\/08\/160823-proxima-centauri-b.jpg 750w\" sizes=\"(max-width: 630px) 100vw, 630px\"><figcaption data-nosnippet=\"\" id=\"caption-attachment-269649\" class=\"wp-caption-text\">An artist\u2019s conception shows Proxima Centauri b orbiting its parent star, a red dwarf, with the two other stars of the Alpha Centauri system in the far background. (Credit: M. Kornmesser \/ ESO)<\/figcaption><\/figure>\n<p>The rumors you\u2019ve heard&nbsp;are mostly true: Scientists say the star that\u2019s closest to our solar system has a planet that could be at the right temperature for liquid water and life.<\/p>\n<p>The star is called Proxima Centauri, a red dwarf that\u2019s part of the Alpha Centauri system, 4.2 light-years away. The planet is called Proxima Centauri b, and it\u2019s a terrestrial world whose existence has now been confirmed after 16 years of study.<\/p>\n<p>It\u2019s not yet known whether Proxima b has an atmosphere, or liquid water. But the computer models don\u2019t rule out the possibility. That would make it the closest known exoplanet \u2013 and the closest known exoplanet with the potential for life.<\/p>\n<p>As such, it could be the nearest haven for humanity in case things go horribly wrong in our own solar system.&nbsp;And it just so happens that scientists are working on a robotic mission to the Alpha Centauri system: The Breakthrough Starshot initiative received a $100 million kick-start from Russian billionaire Yuri Milner in April.<\/p>\n<p>\u201cWe expect either to characterize it, if we get lucky, or maybe visit it in a couple of centuries,\u201d Guillem Anglada-Escude, an astronomer at Queen Mary University of London, told reporters.<\/p>\n<p><iframe title=\"The exoplanet next door\" src=\"https:\/\/www.youtube.com\/embed\/aOTWo6_602Q?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" referrerpolicy=\"strict-origin-when-cross-origin\" allowfullscreen=\"\" data-ratio=\"0.5625\" data-width=\"800\" data-height=\"450\" style=\"display: block; margin: 0px; width: 800px; height: 450px;\"><\/iframe><\/p>\n<p>Word about Proxima b started leaking out earlier this month, sparked by&nbsp;a report in the German magazine Der Spiegel. Anglada-Escude and his colleagues&nbsp;held off on confirming Der Spiegel\u2019s claims, but today the details came out in the journal Nature.<\/p>\n<p>The planet is at least 30 percent more massive than Earth, and makes one circuit around Proxima Centauri every 11.2 Earth days. Those figures imply that the planet comes&nbsp;as close as 4.6 million miles to its parent star.<\/p>\n<p>If Proxima Centauri were like our sun, the planet would be blazingly&nbsp;hot. But because red dwarfs are much dimmer, scientists say Proxima b should have an Earthlike range of temperatures, from 22 degrees below zero Fahrenheit (-30 degrees Celsius) on its dark side to 86 degrees F (30 degrees C) on its light side.<\/p>\n<p>That would make it possible for water&nbsp;to exist in liquid form, which astrobiologists regard as a key requirement for life.<\/p>\n<p>The scientists\u2019 calculations assume that the planet has an Earthlike, heat-trapping atmosphere, and that the planet\u2019s rotation is tidally locked so that one side is constantly facing the star.<\/p>\n<p>Because the scientists have to make&nbsp;such assumptions without the data to back them up, they also have to hedge their bets as to the planet\u2019s habitability. As a result, the rumors claiming that Proxima b could be inhabited by, say, \u201cAvatar\u201d-like space travelers aren\u2019t supported by the facts.<\/p>\n<figure id=\"attachment_269662\" aria-describedby=\"caption-attachment-269662\" style=\"width: 630px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full-width wp-image-269662\" src=\"https:\/\/cdn.geekwire.com\/wp-content\/uploads\/2016\/08\/160823-proxima-centauri-b-terrain-630x409.jpg\" alt=\"Proxima Centauri b terrain\" width=\"630\" height=\"409\" srcset=\"https:\/\/cdn.geekwire.com\/wp-content\/uploads\/2016\/08\/160823-proxima-centauri-b-terrain-630x409.jpg 630w, https:\/\/cdn.geekwire.com\/wp-content\/uploads\/2016\/08\/160823-proxima-centauri-b-terrain-768x499.jpg 768w, https:\/\/cdn.geekwire.com\/wp-content\/uploads\/2016\/08\/160823-proxima-centauri-b-terrain.jpg 1024w\" sizes=\"(max-width: 630px) 100vw, 630px\"><figcaption data-nosnippet=\"\" id=\"caption-attachment-269662\" class=\"wp-caption-text\">An artist\u2019s conception shows a view of the surface of the planet Proxima b, with the red dwarf Proxima Centauri near the horizon. (Credi:t: M. Kornmesser \/ ESO)<\/figcaption><\/figure>\n<p>\u201cDo we know anything about the atmosphere or the water? We don\u2019t,\u201d&nbsp;said&nbsp;the University of G\u00f6ttingen\u2019s Ansgar Reiners, a co-author of the&nbsp;study. \u201cWe have no further information about this planet, but of course we can calculate&nbsp;probabilities, whether there is an atmosphere or water. This has been done intensively as well \u2013&nbsp;and from what we know, at least, there is a non-zero probability that there is an atmosphere.\u201d<\/p>\n<p>He said the biggest question is whether the planet has liquid water on its surface, like Earth, or is totally dry. The answer depends on the details of the planet\u2019s formation, and also whether its reservoirs of water were fed by comets and icy asteroids, as was the case for Earth.<\/p>\n<p>Reiners acknowledged that Proxima b receives much more&nbsp;high-energy radiation than Earth does. That comes with the territory for red dwarfs, also known as M-dwarfs, which are the most common stars in our Milky Way galaxy.<\/p>\n<p>The radiation question led Artie Hatzes of the Thuringian State Observatory to lay out some caveats in a commentary also published by Nature today.&nbsp;It\u2019s not yet known whether Proxima b has a protective magnetic field, for example. The X-ray flux from Proxima Centauri may have eroded the planet\u2019s atmosphere, or hindered the development of life, Hatzes said.<\/p>\n<p>\u201cUntil we understand what makes a planet habitable, it is better to say that Proxima Centauri b lies in a temperate zone (the right temperature) rather than a habitable zone (the right conditions to support life),\u201d he wrote.<\/p>\n<figure id=\"attachment_269663\" aria-describedby=\"caption-attachment-269663\" style=\"width: 630px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full-width wp-image-269663\" src=\"https:\/\/cdn.geekwire.com\/wp-content\/uploads\/2016\/08\/160823-proxima-centauri-b-compare-630x428.jpg\" alt=\"Habitable zone for Proxima Centauri b\" width=\"630\" height=\"428\" srcset=\"https:\/\/cdn.geekwire.com\/wp-content\/uploads\/2016\/08\/160823-proxima-centauri-b-compare-630x428.jpg 630w, https:\/\/cdn.geekwire.com\/wp-content\/uploads\/2016\/08\/160823-proxima-centauri-b-compare-768x522.jpg 768w, https:\/\/cdn.geekwire.com\/wp-content\/uploads\/2016\/08\/160823-proxima-centauri-b-compare.jpg 1024w\" sizes=\"auto, (max-width: 630px) 100vw, 630px\"><figcaption data-nosnippet=\"\" id=\"caption-attachment-269663\" class=\"wp-caption-text\">An infographic compares Mercury\u2019s orbit (left) with the orbit of the planet around Proxima Centauri (right). Proxima Centauri is smaller and cooler than our sun, and the planet orbits much closer to its star than Mercury. Click on the image for a larger version. (Credit: M. Kornmesser and G. Coleman \/ ESO)<\/figcaption><\/figure>\n<p>Anglada-Escude said he and his colleagues think&nbsp;Hatzes\u2019 assessment is too pessimistic. \u201cFor sure the difference between Earth and this planet is that this is receiving much more high-energy radiation, but we don\u2019t think it\u2019s a showstopper here,\u201d he said.<\/p>\n<p>Proxima b\u2019s detection demonstrates how exacting the planet-hunting business has become.<\/p>\n<p>The initial rounds of observations were made by two telescopes at the European Southern Observatory in Chile between 2000 and 2014. Those readings pointed to a faint \u201cDoppler wobble\u201d in the spectral signature of the light from Proxima Centauri.<\/p>\n<p>The back-and-forth effect suggested that the gravitational influence of a planet might be pulling the star to and fro, but the effect was so subtle&nbsp;that astronomers couldn\u2019t confirm that a planet existed.<\/p>\n<p>Then, from January to March of this year, the astronomers conducted an intensive 60-night round of \u201cPale Red Dot\u201d observations, using the ESO\u2019s High Accuracy Radial Velocity Planet Searcher, or HARPS.<\/p>\n<p>When they combined the older data with this year\u2019s Pale Red Dot data, they came up with the hoped-for confirmation. They made additional spectroscopic observations to make sure the effect they were seeing was caused by a planet\u2019s influence and not by stellar activity.<\/p>\n<p>\u201cThe significance of the detection goes sky-high,\u201d Anglada-Escude said.<\/p>\n<figure id=\"attachment_269664\" aria-describedby=\"caption-attachment-269664\" style=\"width: 630px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full-width wp-image-269664\" src=\"https:\/\/cdn.geekwire.com\/wp-content\/uploads\/2016\/08\/160823-proxima-centauri-b-eso-630x668.jpg\" alt=\"Telescope and stars\" width=\"630\" height=\"668\" srcset=\"https:\/\/cdn.geekwire.com\/wp-content\/uploads\/2016\/08\/160823-proxima-centauri-b-eso-630x668.jpg 630w, https:\/\/cdn.geekwire.com\/wp-content\/uploads\/2016\/08\/160823-proxima-centauri-b-eso-768x814.jpg 768w, https:\/\/cdn.geekwire.com\/wp-content\/uploads\/2016\/08\/160823-proxima-centauri-b-eso.jpg 966w\" sizes=\"auto, (max-width: 630px) 100vw, 630px\"><figcaption data-nosnippet=\"\" id=\"caption-attachment-269664\" class=\"wp-caption-text\">This picture combines a view of the southern skies over the ESO 3.6-meter telescope at the La Silla Observatory in Chile with images of the stars Proxima Centauri (lower right) and the double star Alpha Centauri AB (lower left) from the Hubble Space Telescope. (Credits: Y. Beletsky \/ LCO \/ ESO \/ ESA \/ NASA \/ M. Zamani)<\/figcaption><\/figure>\n<p>Now the Pale Red Dot campaign is finished, and astronomers will have to use&nbsp;other methods to learn more about Proxima b.<\/p>\n<p>There\u2019s a slight chance that NASA\u2019s James Webb Space Telescope, due for launch in 2018, could gather data about the planet\u2019s atmosphere.&nbsp;But Reiners said a mission customized for Proxima b&nbsp;is more&nbsp;likely to provide insights.<\/p>\n<p>\u201cPhysics allows you to actually image the planet itself, and this is certainly something that will be going on over&nbsp;the next years, the next decades,\u201d he said. \u201cWe are quite far from it right now.\u201d<\/p>\n<p>This week\u2019s announcement could heighten interest in the Breakthrough Starshot project as well. But because of the distances involved, the Starshot nano-probes won\u2019t get to the Alpha Centauri system for decades, even under the best-case scenario. And using current propulsion technology, it would take tens of thousands of years to send humans&nbsp;to Proxima B.<\/p>\n<p>Does that sound like a long time? In his commentary, Hatzes observed that if life forms exist on Proxima b, there\u2019s no need for us to hurry on their account.<\/p>\n<p>\u201cInterestingly, M-dwarf stars are long-lived, and Proxima Centauri will exist for several hundreds or thousands of times longer than the sun,\u201d he wrote. \u201cAny life on the planet could still be evolving long after our sun has died.\u201d<\/p>\n<p><em>Anglada-Escude and Reiners are among 31 authors of the paper published in Nature, titled \u201cA Terrestrial Planet Candidate in a Temperate Orbit Around Proxima Centauri.\u201d<\/em><\/p>\n","protected":false},"excerpt":{"rendered":"<p>An artist\u2019s conception shows Proxima Centauri b orbiting its parent star, a red dwarf, with the two other stars of the Alpha Centauri system in the far background. (Credit: M. Kornmesser \/ ESO) The rumors you\u2019ve heard&nbsp;are mostly true: Scientists say the star that\u2019s closest to our solar system has a planet that could be [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"inline_featured_image":false,"footnotes":"","_links_to":"","_links_to_target":""},"categories":[2],"tags":[3752,559,4709,3621],"class_list":["post-19279","post","type-post","status-publish","format-standard","hentry","category-news","tag-alpha-centauri","tag-exoplanets","tag-planets","tag-proxima-centauri"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/19279"}],"collection":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/comments?post=19279"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/19279\/revisions"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=19279"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=19279"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=19279"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}