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The Webb telescope has released its very first exoplanet image – here’s what we can learn from it

<p>Did you ever want to see an alien world? A planet orbiting a distant star, light years from the Sun? Well, the <a href="https://webb.nasa.gov/" target="_blank" rel="noopener">James Webb Space Telescope (JWST)</a> has just returned its first-ever picture of just that – a planet orbiting a distant star.</p> <p>The <a href="https://blogs.nasa.gov/webb/2022/09/01/nasas-webb-takes-its-first-ever-direct-image-of-distant-world/?utm_source=TWITTER&amp;utm_medium=NASAWebb&amp;utm_campaign=NASASocial&amp;linkId=179637235" target="_blank" rel="noopener">new images</a> reveal JWST will be a fantastic tool for astronomers aiming to improve their knowledge of exoplanets (planets around other stars) – even better than we had hoped it would be!</p> <p>But for those who’ve grown up on a diet of Star Trek, Star Wars, and myriad other works of science fiction, the images may be underwhelming. No wonderful swirling clouds, in glorious or muted colours. Instead, we just see a blob – a single point of light.</p> <p>So why do these observations have astronomers buzzing with excitement? And what might we learn in the months and years to come?</p> <p><strong>Observing hidden worlds</strong></p> <p>Over the past three decades, we have lived through a great revolution – the dawn of the Exoplanet Era. Where we once knew of no planets orbiting distant stars, and wondered whether the Solar System was unique, we now know planets are everywhere.</p> <figure><iframe src="https://www.youtube.com/embed/yv4DbU1CWAY?wmode=transparent&amp;start=0" width="440" height="260" frameborder="0" allowfullscreen="allowfullscreen"></iframe><figcaption><em><span class="caption">The history of the first 5,000 alien worlds discovered – the dawn of the Exoplanet Era.</span></em></figcaption></figure> <p>At the time of writing, the number of known exoplanets <a href="https://exoplanetarchive.ipac.caltech.edu/" target="_blank" rel="noopener">stands at 5,084</a>, and the count grows larger with every week.</p> <p>But the overwhelming majority of those exoplanets are detected indirectly. They orbit so close to their host stars that, with current technology, we simply cannot see them directly. Instead, we observe their host stars doing something unexpected, and <a href="https://theconversation.com/explainer-how-to-find-an-exoplanet-part-1-56682" target="_blank" rel="noopener">infer from that the presence</a> of their unseen planetary companions.</p> <p>Of all those alien worlds, only a handful have been seen directly. The poster child for such systems is <a href="https://en.wikipedia.org/wiki/HR_8799" target="_blank" rel="noopener">HR 8799</a>, whose four giant planets have been imaged so frequently that astronomers have produced a movie showing them moving in their orbits around their host star.</p> <figure><iframe src="https://www.youtube.com/embed/KVgKidAuf4o?wmode=transparent&amp;start=0" width="440" height="260" frameborder="0" allowfullscreen="allowfullscreen"></iframe><figcaption><em><span class="caption">The first video of exoplanets orbiting their star. HR 8799 host four super-Jupiters, and it took seven years of imaging data to produce this movie.</span></em></figcaption></figure> <p><strong>Enter HIP 65426b</strong></p> <p>To gather JWST’s first direct images of an exoplanet, astronomers turned the telescope towards the star HIP 65426, whose massive planetary companion HIP 65426b was <a href="https://ui.adsabs.harvard.edu/abs/2017A%26A...605L...9C/abstract" target="_blank" rel="noopener">discovered using direct imaging back in 2017</a>.</p> <p>HIP 65426b is unusual in several ways – all of which act to make it a particularly “easy” target for direct imaging. First, it is a long way from its host star, orbiting roughly 92 times farther from HIP 65426 than the distance between Earth and the Sun. That puts it around 14 billion kilometres from its star. From our point of view, this makes for a “reasonable” distance from the star in the sky, making it easier to observe.</p> <p>Next, HIP 65426b is a behemoth of a world – thought to be several times the mass of the Solar System’s biggest planet, Jupiter. On top of that, it was also previously found to be remarkably hot, with temperature at its cloud tops measuring at least 1,200℃.</p> <p>This combination of the planet’s size and temperature means it is intrinsically bright (for a planet).</p> <figure class="align-center zoomable"><em><a href="https://images.theconversation.com/files/482618/original/file-20220904-39859-xghmli.png?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=1000&amp;fit=clip"><img src="https://images.theconversation.com/files/482618/original/file-20220904-39859-xghmli.png?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;fit=clip" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px" srcset="https://images.theconversation.com/files/482618/original/file-20220904-39859-xghmli.png?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=600&amp;h=444&amp;fit=crop&amp;dpr=1 600w, https://images.theconversation.com/files/482618/original/file-20220904-39859-xghmli.png?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=600&amp;h=444&amp;fit=crop&amp;dpr=2 1200w, https://images.theconversation.com/files/482618/original/file-20220904-39859-xghmli.png?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=600&amp;h=444&amp;fit=crop&amp;dpr=3 1800w, https://images.theconversation.com/files/482618/original/file-20220904-39859-xghmli.png?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;h=558&amp;fit=crop&amp;dpr=1 754w, https://images.theconversation.com/files/482618/original/file-20220904-39859-xghmli.png?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=754&amp;h=558&amp;fit=crop&amp;dpr=2 1508w, https://images.theconversation.com/files/482618/original/file-20220904-39859-xghmli.png?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=754&amp;h=558&amp;fit=crop&amp;dpr=3 2262w" alt="Four images of HIP 65426b, at four different wavelengths of infrared light." /></a></em><figcaption><em><span class="caption">JWST’s first images of an alien world, HIP 65426b, are shown at the bottom of a wider image showing the planet’s host star. The images were taken at different wavelengths of infrared light.</span> Image: <span class="attribution"><span class="source">NASA/ESA/CSA, A Carter (UCSC), the ERS 1386 team, and A. Pagan (STScI).</span></span></em></figcaption></figure> <p><strong>How were the images taken, and what do they show us?</strong></p> <p>Under normal circumstances, the light from HIP 65426 would utterly overwhelm that from HIP 65426b, despite the distance between them.</p> <p>To get around this problem, JWST <a href="https://exoplanets.nasa.gov/news/1577/a-new-view-of-exoplanets-with-webb/" target="_blank" rel="noopener">carries several “coronagraphs”</a>, instruments that let the telescope block the light from a bright star to look for fainter objects beside it. This is a bit like blocking the headlights of a car with your hand to see whether your friend has climbed out to say hello.</p> <p>Using these coronagraphs, JWST took a series of images of HIP 65426b, each taken at a different wavelength of infrared light. In each image, the planet can be clearly seen – a single bright pixel offset from the location of its obscured stellar host.</p> <p>The images are far from your standard science fiction fare. But they show that the planet was easily detected, standing out like a sore thumb against the dark background of space.</p> <p>The researchers who led the observations (<a href="https://arxiv.org/pdf/2208.14990" target="_blank" rel="noopener">detailed on the preprint server arXiv</a>) found that JWST is performing around ten times better than expected – a result that has astronomers around the globe excited to see what comes next.</p> <p>Using their observations, they determined the mass of HIP 65426b (roughly seven times that of Jupiter). Beyond that, the data reveal the planet is hotter than previously thought (with cloud tops close to 1,400℃), and somewhat smaller than expected (with a diameter about 92% that of Jupiter).</p> <p>These images paint a picture of an utterly alien world, different to anything in the Solar System.</p> <p><strong>A signpost to the future</strong></p> <p>The observations of HIP 65426b are just the first sign of what JWST can do in imaging planets around other stars.</p> <p>The incredible precision of the imaging data suggests JWST will be able to obtain direct observations of planets smaller than previously expected. Rather than being limited to planets more massive than Jupiter, it should be able to see planets comparable to, or even smaller than, Saturn.</p> <p>This is a really exciting. You see, a basic rule of astronomy is that there are lots more small things than big things. The fact JWST should be able to see smaller and fainter planets than expected will <em>greatly</em> increase the number of possible targets available for astronomers to study.</p> <p>Beyond that, the precision with which JWST carried out these measurements suggests we will be able to learn far more about their atmospheres than expected. Repeated observations with the telescope could even reveal details of how those atmospheres vary with time.</p> <p>In the coming years, then, expect to see many more images of alien worlds, taken by JWST. While those pictures might not look like those in science fiction, they will still revolutionise our understanding of planets around other stars.<!-- Below is The Conversation's page counter tag. Please DO NOT REMOVE. --><img style="border: none !important; box-shadow: none !important; margin: 0 !important; max-height: 1px !important; max-width: 1px !important; min-height: 1px !important; min-width: 1px !important; opacity: 0 !important; outline: none !important; padding: 0 !important;" src="https://counter.theconversation.com/content/189876/count.gif?distributor=republish-lightbox-basic" alt="The Conversation" width="1" height="1" /><!-- End of code. If you don't see any code above, please get new code from the Advanced tab after you click the republish button. The page counter does not collect any personal data. More info: https://theconversation.com/republishing-guidelines --></p> <p><em><a href="https://theconversation.com/profiles/jonti-horner-3355" target="_blank" rel="noopener">Jonti Horner</a>, Professor (Astrophysics), <a href="https://theconversation.com/institutions/university-of-southern-queensland-1069" target="_blank" rel="noopener">University of Southern Queensland</a></em></p> <p><em>This article is republished from <a href="https://theconversation.com" target="_blank" rel="noopener">The Conversation</a> under a Creative Commons license. Read the <a href="https://theconversation.com/the-webb-telescope-has-released-its-very-first-exoplanet-image-heres-what-we-can-learn-from-it-189876" target="_blank" rel="noopener">original article</a>.</em></p> <p><em>Image: NASA/ESA/CSA, A Carter (UCSC), the ERS 1386 team, and A. Pagan (STScI)</em></p>

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Two nearby, newly discovered exoplanets mirror Earth

<p>Scientists have found two rocky exoplanets – not much larger than Earth – orbiting a star so close to us that they are practically in our solar system’s backyard.</p> <p>The star, HD 260655, is a low-mass M-class star, a type known as a red dwarf, about 33 light years away. The discovery was announced by Rafael Luque of the University of Chicago and the Institute of Astrophysics of Andalusia, Spain, at a recent meeting of the American Astronomical Society in the US.</p> <p>To put that distance into perspective, 33 light years is so close that if you constructed a scale model of the galaxy, in which the Sun was in Pasadena (site of the meeting) and HD 260655 was in neighbouring Hollywood (18km away), then the centre of our galaxy (the Milky Way) would be somewhere around Nepal.</p> <p>That’s important because it puts the two new planets close enough to us to make them prime targets for the recently launched James Webb Space Telescope.</p> <p>The planets were first observed in late 2021, when NASA’s planet-hunting space telescope <a href="https://www.nasa.gov/tess-transiting-exoplanet-survey-satellite" target="_blank" rel="noreferrer noopener">TESS (Transiting Exoplanet Survey Satellite)</a> spotted them passing between us and their star, causing its light to dim as they eclipsed a portion of it.</p> <p>That was interesting enough, but when Luque’s team looked back at prior observations of the same star from telescopes on Earth, they found that its motion appeared to wobble as it was tugged alternately toward and away from us – exactly what would happen if it was being affected by the gravity of orbiting planets. That wobble hadn’t been strong enough to alert scientists to the presence of the planets at the time, but combined with the TESS observations, it was a smoking gun.</p> <div class="newsletter-box"> <div id="wpcf7-f6-p195069-o1" class="wpcf7" dir="ltr" lang="en-US" role="form"> <form class="wpcf7-form mailchimp-ext-0.5.62 spai-bg-prepared init" action="/space/astrophysics/two-nearby-newly-discovered-exoplanets-mirror-earth/#wpcf7-f6-p195069-o1" method="post" novalidate="novalidate" data-status="init"> <p style="display: none !important;"><span class="wpcf7-form-control-wrap referer-page"><input class="wpcf7-form-control wpcf7-text referer-page spai-bg-prepared" name="referer-page" type="hidden" value="https://cosmosmagazine.com/space/" data-value="https://cosmosmagazine.com/space/" aria-invalid="false" /></span></p> <p><!-- Chimpmail extension by Renzo Johnson --></form> </div> </div> <p>Better yet, Luque says, combining the TESS data (which gave the diameter of the two planets by the degree to which they blocked their sun’s light) with the wobble data (which revealed their masses), it was possible to calculate their density. “We found that these planets, despite being slightly larger than the Earth, have a density pretty similar to ours,” he says.</p> <p>This means they aren’t water worlds or gas-dominated worlds like those in our own outer solar system. “Both are consistent with having a composition consistent with rocks,” Luque says.</p> <p>Not that this means they are twins of Earth, let alone suggests that they can support life as we know it. The one nearest to its star might be nearly as hot as Venus, and the other might still have a surface temperature as high as 284°C.</p> <p>But even if they prove to be too hot for complex life, they are important targets for study because they might teach us more about a truly Earthlike world, once we find one at the right distance from its star. “Both are ranked among the ten best targets to look at,” Luque says.</p> <p><!-- Start of tracking content syndication. Please do not remove this section as it allows us to keep track of republished articles --></p> <p><img id="cosmos-post-tracker" style="opacity: 0; height: 1px!important; width: 1px!important; border: 0!important; position: absolute!important; z-index: -1!important;" src="https://syndication.cosmosmagazine.com/?id=195069&amp;title=Two+nearby%2C+newly+discovered+exoplanets+mirror+Earth" width="1" height="1" /></p> <p><!-- End of tracking content syndication --></p> <div id="contributors"> <p><em><a href="https://cosmosmagazine.com/space/astrophysics/two-nearby-newly-discovered-exoplanets-mirror-earth/" target="_blank" rel="noopener">This article</a> was originally published on <a href="https://cosmosmagazine.com" target="_blank" rel="noopener">Cosmos Magazine</a> and was written by <a href="https://cosmosmagazine.com/contributor/richard-a-lovett" target="_blank" rel="noopener">Richard A Lovett</a>. Richard A Lovett is a Portland, Oregon-based science writer and science fiction author. He is a frequent contributor to Cosmos.</em></p> <p><em>Image: NASA/JPL-Caltech</em></p> </div>

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