{"id":17883,"date":"2019-11-12T22:04:49","date_gmt":"2019-11-12T14:04:49","guid":{"rendered":"https:\/\/wp-productionenv-bjg9h2g2bgg5b8aa.southeastasia-01.azurewebsites.net\/news\/3-d-climate-modeling-could-fine-tune-the-search-for-faraway-signs-of-alien-life\/"},"modified":"2019-11-12T22:04:49","modified_gmt":"2019-11-12T14:04:49","slug":"3-d-climate-modeling-could-fine-tune-the-search-for-faraway-signs-of-alien-life","status":"publish","type":"post","link":"https:\/\/starpath.global\/news\/3-d-climate-modeling-could-fine-tune-the-search-for-faraway-signs-of-alien-life\/","title":{"rendered":"3-D climate modeling could fine-tune the search for faraway signs of alien life"},"content":{"rendered":"<figure id=\"attachment_532626\" aria-describedby=\"caption-attachment-532626\" style=\"width: 630px\" class=\"wp-caption aligncenter\"><img fetchpriority=\"high\" decoding=\"async\" class=\"size-full-width wp-image-532626\" src=\"https:\/\/cdn.geekwire.com\/wp-content\/uploads\/2019\/11\/191112-mdwarf-630x430.jpg\" alt=\"M-dwarf planet\" width=\"630\" height=\"430\" srcset=\"https:\/\/cdn.geekwire.com\/wp-content\/uploads\/2019\/11\/191112-mdwarf-630x430.jpg 630w, https:\/\/cdn.geekwire.com\/wp-content\/uploads\/2019\/11\/191112-mdwarf-768x524.jpg 768w, https:\/\/cdn.geekwire.com\/wp-content\/uploads\/2019\/11\/191112-mdwarf-1260x860.jpg 1260w, https:\/\/cdn.geekwire.com\/wp-content\/uploads\/2019\/11\/191112-mdwarf.jpg 1500w\" sizes=\"(max-width: 630px) 100vw, 630px\"><figcaption data-nosnippet=\"\" id=\"caption-attachment-532626\" class=\"wp-caption-text\">An artist\u2019s conception shows a hypothetical planet with two moons orbiting within the habitable zone of an M-dwarf star. (NASA \/ Harvard-Smithsonian Center for Astrophysics Illustration \/ D. Aguilar)<\/figcaption><\/figure>\n<p>Astronomers have identified thousands of stars that have planets, and that number could mushroom even faster when waves of next-generation telescopes come online. But where are the best places to look for life?<\/p>\n<p>A newly released study focuses on the most plentiful category of stars in our Milky Way galaxy \u2014 M-dwarf stars, also known as red dwarfs \u2014 and delivers good news as well as bad news for astrobiologists.<\/p>\n<p>The good news is that 3-D climate modeling of atmospheric chemistry can produce a more comprehensive assessment of a planet\u2019s potential habitability.<\/p>\n<p>On a basic level, a planetary system\u2019s habitable zone is defined as the doughnut-shaped region surrounding a star that gets just the right amount of radiation to keep water in a liquid state, rather than having it boil off or freeze.<\/p>\n<p>Astrobiologists start with that criterion because on Earth, some form of life can be found virtually anywhere liquid water exists. But for alien stars, and particularly M-dwarfs, the situation is more complex.<\/p>\n<p>The new findings, due for publication this week in the Astrophysical Journal, support the view that planets orbiting active M-dwarf stars are vulnerable to losing significant amounts of water, due to vaporization caused by ultraviolet radiation.<\/p>\n<p>What\u2019s more, planets with too-thin layers of ozone are likely to let too much UV light pass through their atmospheres. That radiation would deal a killing blow to life as we know it, even if there\u2019s liquid water at the surface.<\/p>\n<p><iframe title=\"The Last Star in the Universe \u2013 Red Dwarfs Explained\" src=\"https:\/\/www.youtube.com\/embed\/LS-VPyLaJFM?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>The computer model described in the Astrophysical Journal paper takes advantage of 3-D climate modeling for chemical reactions in alien atmospheres. That approach literally adds another dimension to the process for determining habitability.<\/p>\n<p>\u201c3-D photochemistry plays a huge role because it provides heating or cooling, which can affect the thermodynamics and perhaps the atmospheric composition of a planetary system,\u201d study lead author Howard Chen, a Ph.D. candidate at Northwestern University, said in a news release.<\/p>\n<p>\u201cThese kinds of models have not really been used at all in the exoplanet literature studying rocky planets because they are so computationally expensive,\u201d Chen said. \u201cOther photochemical models studying much larger planets, such as gas giants and hot Jupiters, already show that one cannot neglect chemistry when investigating climate.\u201d<\/p>\n<p>The team\u2019s findings are likely to dim hopes of finding life on Proxima Centauri b, the closest planet beyond our solar system. Proxima b is technically inside the habitable zone of its parent star, an M-dwarf, but that star throws off strong flares.<\/p>\n<p>Astronomers have already noted that Proxima b\u2019s radiation environment could be problematic. The same goes for TRAPPIST-1 e, another M-dwarf exoplanet that has previously been judged as potentially habitable. The newly published paper reinforces that pessimistic view.<\/p>\n<p>\u201cIt doesn\u2019t necessarily preclude habitability on Proxima b and TRAPPIST-1e like planets \u2026 but it does further the idea that the stellar radiation environment for planets around M-dwarf stars may make it very challenging to maintain water vapor on terrestrial planets,\u201d said study co-author Eric Wolf, an astronomer at the University of Colorado at Boulder.<\/p>\n<p>Wolf is affiliated with the NASA Astrobiology Institute\u2019s Virtual Planetary Laboratory, which is headquartered at the University of Washington. He and his colleagues have devoted a lot of attention to the conditions likely to exist on planets around M-dwarf stars, which make up about 70 percent of the Milky Way\u2019s stellar population.<\/p>\n<p>\u201cThese planets could have so-called secondary atmospheres, outgassed by continuing volcanic activity over time. Note that Earth\u2019s atmosphere we enjoy today is a secondary atmosphere,\u201d Wolf told GeekWire in an email. \u201cHowever, continued high levels of stellar activity by M-dwarf stars can pose a significant threat to habitability by stripping away water vapor from the secondary atmosphere and drying out the planets in the long term.\u201d<\/p>\n<p>It\u2019s not all bad news, Wolf said. \u201cHoward\u2019s paper also tells us that ideal planet targets will be those that are found around UV-quiet stars, and more so, stars have been quiet over their lifetimes,\u201d he said.<\/p>\n<p>In the years to come, NASA\u2019s James Webb Space Telescope and other next-generation observatories are expected to accelerate the pace of planet discovery, and even make it possible to analyze the atmospheres of alien planets.<\/p>\n<p>\u201cThere are lots of stars and planets out there,\u201d said the study\u2019s senior author, Northwestern University planetary scientist Daniel Horton. \u201cOur study can help limit the number of places we have to point our telescopes.\u201d<\/p>\n<p><em>Authors of the Astrophysical Journal paper, titled \u201cHabitability and Spectroscopic Observability of Warm M-Dwarf Exoplanets Evaluated With a 3D Chemistry-Climate Model,\u201d include Chen, Wolf and Horton as well as Zhuchang Zhan.<\/em><\/p>\n","protected":false},"excerpt":{"rendered":"<p>An artist\u2019s conception shows a hypothetical planet with two moons orbiting within the habitable zone of an M-dwarf star. (NASA \/ Harvard-Smithsonian Center for Astrophysics Illustration \/ D. Aguilar) Astronomers have identified thousands of stars that have planets, and that number could mushroom even faster when waves of next-generation telescopes come online. But where are [&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":[1874,559,4709,3621,4925,3403],"class_list":["post-17883","post","type-post","status-publish","format-standard","hentry","category-news","tag-astrobiology","tag-exoplanets","tag-planets","tag-proxima-centauri","tag-red-dwarfs","tag-trappist-1"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/17883"}],"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=17883"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/17883\/revisions"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=17883"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=17883"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=17883"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}