[{"command":"openDialog","selector":"#drupal-modal","settings":null,"data":"\u003Cdiv id=\u0022republish_modal_form\u0022\u003E\u003Cform class=\u0022modal-form-example-modal-form ecl-form\u0022 data-drupal-selector=\u0022modal-form-example-modal-form\u0022 action=\u0022\/it\/article\/modal\/7148\u0022 method=\u0022post\u0022 id=\u0022modal-form-example-modal-form\u0022 accept-charset=\u0022UTF-8\u0022\u003E\u003Cp\u003EHorizon articles can be republished for free under the Creative Commons Attribution 4.0 International (CC BY 4.0) licence.\u003C\/p\u003E\n      \u003Cp\u003EYou must give appropriate credit. We ask you to do this by:\u003Cbr \/\u003E\n      1) Using the original journalist\u0027s byline\u003Cbr \/\u003E\n      2) Linking back to our original story\u003Cbr \/\u003E\n      3) Using the following text in the footer: This article was originally published in \u003Ca href=\u0027#\u0027\u003EHorizon, the EU Research and Innovation magazine\u003C\/a\u003E\u003C\/p\u003E\n      \u003Cp\u003ESee our full republication guidelines \u003Ca href=\u0027\/horizon-magazine\/republish-our-stories\u0027\u003Ehere\u003C\/a\u003E\u003C\/p\u003E\n      \u003Cp\u003EHTML for this article, including the attribution and page view counter, is below:\u003C\/p\u003E\u003Cdiv class=\u0022js-form-item form-item js-form-type-textarea form-item-body-content js-form-item-body-content ecl-form-group ecl-form-group--text-area form-no-label ecl-u-mv-m\u0022\u003E\n        \n\u003Cdiv\u003E\n  \u003Ctextarea data-drupal-selector=\u0022edit-body-content\u0022 aria-describedby=\u0022edit-body-content--description\u0022 id=\u0022edit-body-content\u0022 name=\u0022body_content\u0022 rows=\u00225\u0022 cols=\u002260\u0022 class=\u0022form-textarea ecl-text-area\u0022\u003E\u003Ch2\u003E\u0027We\u0027ve found dozens of potentially habitable planets - now we need to study them in detail\u0027\u003C\/h2\u003E\u003Cp\u003E\u003Cstrong\u003EIn 2017, his SPECULOOS project discovered seven Earth-sized planets around the TRAPPIST-1 system, one of the most intriguing planetary systems found so far \u2013 and now the hunt is on for more weird, wonderful, and even Earth-like worlds.\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EWhat were the goals of the SPECULOOS project?\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u2018The SPECULOOS project aimed to develop facilities composed of several robotic telescopes to search for exoplanets \u2013 planets orbiting around other stars \u2013 that transit very nearby (Earth) and around very tiny small stars (ultra-cool dwarfs), basically, the least massive kind of star. The goal was to search for planets that are potentially habitable and that are well-suited for detailed (atmospheric) characterisation by (NASA\u2019s) upcoming James Webb Space Telescope (due to launch in 2021). Now we really want to move from exoplanet detection to exoplanet detailed study characterisation.\u003C\/p\u003E\u003Cp\u003E\u2018In 2017, (the project) achieved a wonderful result because it detected the \u003Ca href=\u0022https:\/\/erc.europa.eu\/news\/erc-projects-behind-exoplanets-discovery\u0022 target=\u0022_blank\u0022 rel=\u0022noopener noreferrer\u0022\u003Efamous TRAPPIST-1 system\u003C\/a\u003E, which is composed of seven Earth-sized planets around one of the brightest and nearest SPECULOOS targets. This system is the best system so far for the study of temperate, potentially habitable planets with James Webb.\u2019\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EHow was the TRAPPIST-1 system detected?\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u2018In 2009, we installed a robotic telescope in Chile called TRAPPIST (Transiting Planets and Planetesimals Small Telescope). The main goal was to do exoplanet transit photometry, so to confirm or search for transits of planets (by detecting the change in light intenstity when a planet passes in front of its star).\u003C\/p\u003E\u003Cp\u003E\u2018In 2016, we monitored (a system) very intensively. We had already announced the discovery of three planets in the system in spring 2016. We went on monitoring, also with (NASA\u2019s) Spitzer telescope, and it resulted in the detection of seven planets instead of three.\u2019\u003C\/p\u003E\u003Cp\u003E\u003Cfigure role=\u0022group\u0022 class=\u0022@alignleft@\u0022\u003E\n\u003Cimg alt=\u0022Scientists detect the presence of exoplanets such as those in the TRAPPIST-1 system by measuring the drop in light intensity when the planets pass in front of their stars. Image credit: NASA\/JPL-Caltech\u0022 height=\u0022450\u0022 src=\u0022\/research-and-innovation\/sites\/default\/files\/hm\/IMCEUpload\/trappist-transit.gif\u0022 title=\u0022Scientists detect the presence of exoplanets such as those in the TRAPPIST-1 system by measuring the drop in light intensity when the planets pass in front of their stars. Image credit: NASA\/JPL-Caltech\u0022 width=\u0022600\u0022\u003E\n\u003Cfigcaption class=\u0022italic mb-4\u0022\u003EScientists detect the presence of exoplanets such as those in the TRAPPIST-1 system by measuring the drop in light intensity when the planets pass in front of their stars. Image credit: NASA\/JPL-Caltech\u003C\/figcaption\u003E\n\u003C\/figure\u003E\n\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EHow many exoplanets have we found so far, and how many of those are potentially habitable?\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u2018Since the discovery of \u003Ca href=\u0022https:\/\/www.theguardian.com\/science\/2019\/oct\/08\/nobel-prize-in-physics-awarded-for-research-on-cosmology-and-exoplanets-2019\u0022 target=\u0022_blank\u0022 rel=\u0022noopener noreferrer\u0022\u003E51 Pegasi b\u003C\/a\u003E in 1995, more than 4,000 exoplanets have been detected. Now we know for sure that most stars of our galaxy and in the universe harbour their own planetary system. But only a few dozen of these exoplanets (found) are potentially habitable. We want to detect more like the TRAPPIST-1 planets because they will present more opportunities to know more about the atmospheric and surface properties (of temperate rocky planets).\u2019\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EWhat makes an exoplanet likely to be habitable?\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u2018Well, liquid water on the surface of a rocky planet. For this to be possible you need a solid surface, a rocky world, but you need an atmosphere that is dense enough to make pressure and temperature (possible) for liquid water. You (also) need a star that is not too harsh in terms of high energy radiation, that does not erode the atmosphere of the planet. The survival of an atmosphere is something that is dependent on the properties of the host star, too.\u2019\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EWhat do we know about exoplanets so far?\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u2018We\u2019ve learned from exoplanet discoveries that the diversity of planetary systems is very,\u0026nbsp;very large. The only planets we knew of were in the solar system, so we thought you had rocky small planets near a star, and giant planets rich in gas (far away). But it\u2019s not at all the case. You can have planets that are rich in gas and migrate inwards. Sometimes you have a very compact system of planets like TRAPPIST-1. Sometimes you find planets in very eccentric orbits. You have planets around double stars, and planets that are free-floating in the interstellar void that have been ejected by young systems. So, the diversity of these mechanisms of planetary formation is really fascinating.\u2019\u003C\/p\u003E\u003Cp\u003E\u003Cfigure role=\u0022group\u0022 class=\u0022@alignleft@\u0022\u003E\n\u003Cimg alt=\u0022In 2016, Dr Gillon discovered a system of seven Earth-sized planets orbiting an ultra-cool dwarf called TRAPPIST-1 (artist\u0027s impression). Image credit - NASA\/JPL-Caltech\u0022 height=\u00223000\u0022 src=\u0022\/research-and-innovation\/sites\/default\/files\/hm\/IMCEUpload\/PIA21422.jpg\u0022 title=\u0022In 2016, Dr Gillon discovered a system of seven Earth-sized planets orbiting an ultra-cool dwarf called TRAPPIST-1 (artist\u0027s impression). Image credit - NASA\/JPL-Caltech\u0022 width=\u00226000\u0022\u003E\n\u003Cfigcaption class=\u0022italic mb-4\u0022\u003EIn 2016, Dr Gillon discovered a system of seven Earth-sized planets orbiting an ultra-cool dwarf called TRAPPIST-1 (artist\u0027s impression). Image credit - NASA\/JPL-Caltech\u003C\/figcaption\u003E\n\u003C\/figure\u003E\n\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003ESo there are some free-floating exoplanets?\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u2018Yes, some have been detected by (gravitational) microlensing techniques. It has been inferred that there must be billions of them in the galaxy, ejected from young systems by interactions with other planets (or with a star). Fortunately, Earth is not among them.\u2019\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EWhat are some of the biggest unanswered questions in exoplanet science?\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u2018I would say the frequency of really habitable planets is one of the main goals of the field now, to assess the frequency of planets with liquid water on the surface. Are planets around low mass stars habitable? Because these low mass stars tend to have high energy irradiation that is much harsher (than our sun).\u003C\/p\u003E\u003Cp\u003E\u2018The habitability of planets around red dwarfs is one of the key topics now in the field. We are (also) still learning the details of the formation of planets, thanks to the diversity of planets we are detecting. We also want to learn more about super-Earths, which do not exist in our solar system, planets between Earth and Neptune (in size).\u2019\u003C\/p\u003E\u003Cp\u003E\u003Cblockquote class=\u0022text-center text-blue font-bold text-2xl w-full lg:w-1\/2 border-2 border-blue p-12 my-8 lg:m-12 lg:-ml-16 float-left\u0022\u003E\n  \u003Cspan class=\u0022text-5xl rotate-180\u0022\u003E\u201c\u003C\/span\u003E\n  \u003Cp class=\u0022font-serif italic\u0022\u003E\u0026#039;Now we know for sure that most stars of our galaxy and in the universe harbour their own planetary system.\u0026#039;\u003C\/p\u003E\n  \u003Cfooter\u003E\n    \u003Ccite class=\u0022not-italic font-normal text-sm text-black\u0022\u003EDr Micha\u00ebl Gillon, University of Li\u00e8ge, Belgium\u003C\/cite\u003E\n  \u003C\/footer\u003E\n\u003C\/blockquote\u003E\n\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EWhat role will ESA\u2019s upcoming CHEOPS telescope, launching on 17 December, play in our understanding of exoplanets?\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u2018It\u2019s a very focused mission, which will do high-precision transit photometry, so measuring very precisely the brightness of transiting planets, to better determine the size of the planet. It\u2019s a follow-up mission, and it will be able to do very detailed precise measurements on selected high-priority exoplanet targets. This is the first mission of its kind.\u2019\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EAre there any other developments that could expand our understanding of exoplanets?\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u2018James Webb (telescope) will be able to make possible very detailed atmospheric characterisation of a large sample of (rocky planets around) low mass stars, and also giant planets (around sun-like stars), using the transit method. But if we are interested in Earth-like planets in Earth-like orbits around sun-like stars, we need to develop direct imaging techniques. These developments are ongoing, but it will take still decades to detect (and study) an Earth twin by direct imaging.\u2019\u003C\/p\u003E\u003Cp\u003E\u003Cem\u003EThe research in this article was funded by the EU\u0027s European Research Council. If you liked this article, please consider sharing it on social media.\u003C\/em\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cem\u003EEditor\u0027s note: The headline of this article was corrected on 4 November to reflect the fact that while scientists have found thousands of exoplanets, only a few dozen are potentially habitable.\u003C\/em\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cdiv class=\u0022moreinfoblock\u0022\u003E\n  \u003Ch3\u003ECHEOPS\u003C\/h3\u003E\n  \u003Cp\u003EOn 17 December 2019, the European Space Agency is expected to launch its \u003Ca href=\u0022https:\/\/sci.esa.int\/web\/cheops\u0022 target=\u0022_blank\u0022 rel=\u0022noopener noreferrer\u0022\u003ECHEOPS satellite\u003C\/a\u003E to look in more detail at some of the exoplanets we\u2019ve already found. The main aim is to better understand their structure in order to test theories of planet formation and evolution.\u003C\/p\u003E\u003Cp\u003EThe on-board telescope, which weighs just 60kg, is designed to precisely measure each exoplanet\u2019s radius and compare it to its estimated mass to understand what it is made of.\u003C\/p\u003E\u003Cp\u003EThe data gathered should also help narrow down future observation targets by identifying planets with an atmosphere, which is necessary for a planet to harbour life.\u003C\/p\u003E\n\u003C\/div\u003E\n\u003C\/p\u003E\u003C\/textarea\u003E\n\u003C\/div\u003E\n\n            \u003Cdiv id=\u0022edit-body-content--description\u0022 class=\u0022ecl-help-block description\u0022\u003E\n      Please copy the above code and embed it onto your website to republish.\n    \u003C\/div\u003E\n  \u003C\/div\u003E\n\u003Cinput autocomplete=\u0022off\u0022 data-drupal-selector=\u0022form-ko7hjwt8cx0yhphcuwyd0ifpiteiwzhru53mcqby3ho\u0022 type=\u0022hidden\u0022 name=\u0022form_build_id\u0022 value=\u0022form-KO7Hjwt8CX0yhphcUwyd0ifpitEiwzHru53mcqby3ho\u0022 \/\u003E\n\u003Cinput data-drupal-selector=\u0022edit-modal-form-example-modal-form\u0022 type=\u0022hidden\u0022 name=\u0022form_id\u0022 value=\u0022modal_form_example_modal_form\u0022 \/\u003E\n\u003C\/form\u003E\n\u003C\/div\u003E","dialogOptions":{"width":"800","modal":true,"title":"Republish this content"}}]