A planet that might be able to hold liquid water has been confirmed orbiting one of our nearest stellar neighbors. The world, called GJ 887 d, sits in the “habitable zone” of its star and lies about 10.7 light years away, roughly 63 trillion miles.<\/p>\n\n\n\n
That is close by space standards, and it puts the planet on a short list of nearby places where scientists may someday look for signs of life. The new analysis also strengthens the case that GJ 887 hosts at least four planets, with hints of a possible fifth.<\/p>\n\n\n\n
GJ 887 is an M dwarf, also called a red dwarf, the most common kind of star in our galaxy. These stars are smaller and dimmer than the Sun, so a planet can orbit closer in and still get a comfortable amount of warmth.<\/p>\n\n\n\n
That setup makes red dwarfs prime targets for planet hunters, but there is a catch. Many are magnetically active, which can muddy planet signals, a bit like trying to hear a whisper in a crowded cafeteria.<\/p>\n\n\n\n
GJ 887 stands out because it is close and bright for its type, and earlier work suggested it is relatively calm. In 2020, a study inScience<\/em><\/a> led by Steven V. Jeffers reported two planets and flagged a longer signal that might have been another world.<\/p>\n\n\n\n The new confirmation comes from the RedDots collaboration, led by C. Hartogh from the University of G\u00f6ttingen and the University of St Andrews. The researchers relied on the radial velocity method, which looks for tiny back-and-forth motions of a star caused by orbiting planets.<\/p>\n\n\n\n Radial velocity works through the Doppler effect, the same shift you notice when a siren changes pitch as it moves past you. Sensitive instruments can spot that change in starlight, revealing a repeating pattern that matches a planet\u2019s orbit.<\/p>\n\n\n\n To firm up the case, the team added 101 new observations from HARPS<\/a> at the European Southern Observatory\u2019s La Silla site in Chile and 12 ultraprecise measurements from ESPRESSO<\/a> on the Very Large Telescope. They also pinned down the star\u2019s rotation at about 39 days, then used a statistical tool called a Gaussian process to model the star\u2019s own noise.<\/p>\n\n\n\n With the extra data, the researchers confirmed four planets around GJ 887. Two were already known, orbiting every 9 and 22 days, while two more were hiding in the noise until the new analysis teased them out.<\/p>\n\n\n\n The standout is GJ 887 d, which circles its star about once every 51 days and falls inside the habitable zone. Its minimum mass is about six and a half times Earth\u2019s, putting it in the “super-Earth” category, meaning bigger than Earth but still far smaller than Neptune. That also makes it the second-closest known habitable-zone planet after Proxima Centauri b.<\/p>\n\n\n\n Not every planet in this system is a life candidate, though. GJ 887 e appears to have a mass similar to Earth but races around the star in about 4.4 days, which is far too close and likely too hot for surface water.<\/p>\n\n\n\n The habitable zone is the orbital range where a rocky planet could, in theory, keep liquid water on its surface. It is not a promise of life, just a temperature starting point.<\/p>\n\n\n\n In the new study, the team estimates GJ 887\u2019s habitable zone spans planets with years between about 43 and 122 days. That places GJ 887 d inside the band, and it also qualifies for inclusion in the Habitable Worlds Catalog<\/a> used by researchers tracking nearby candidates.<\/p>\n\n\n\n But habitability depends on more than distance. A planet\u2019s atmosphere, clouds, and magnetic field can change how much heat it keeps, and red dwarfs can still flare, sending bursts of radiation that may erode atmospheres over time.<\/p>\n\n\n\n So why are astronomers excited about a planet that is still just a dot in the data? The answer is practical, because the next generation of space telescopes will need a target list of nearby worlds where atmospheric “fingerprints” might be detectable.<\/p>\n\n\n\n The Habitable Worlds Observatory<\/a> is being designed with that in mind, aiming to “identify and directly image 25 potentially habitable worlds”. The LIFE concept<\/a> is also in development, exploring a formation-flying space interferometer that would study the heat glow of exoplanet atmospheres.<\/p>\n\n\n\n Because GJ 887 is nearby and bright, the new paper argues the system is a promising candidate for this kind of follow-up. If future instruments can measure gases in GJ 887 d\u2019s atmosphere, they may be able to test whether it looks more like a rocky world, a water-rich planet, or a puffy mini-Neptune.<\/p>\n\n\n\n One big unknown is what GJ 887 d is actually like. The radial velocity method gives a minimum mass, but without a separate measurement of the planet\u2019s size, scientists cannot yet pin down its density, which is key to knowing if it is rocky or wrapped in thick gas.<\/p>\n\n\n\n The data also hinted at a possible fifth planet, labeled GJ 887 f, orbiting in about 2.2 days with a minimum mass around half of Earth. The team did not call it a firm detection and says more observations are needed to figure out what is really causing the signal.<\/p>\n\n\n\n For now, GJ 887 d is best seen as a strong nearby candidate for deeper study rather than a confirmed “second Earth.” Still, with only about 10.7 light years between it and us, it is exactly the kind of world future missions will keep coming back to.<\/p>\n\n\n\n The study was published in Astronomy & Astrophysics<\/em><\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":" A planet that might be able to hold liquid water has been confirmed orbiting one of our nearest stellar neighbors. … <\/p>\nHow the team separated planets from star noise<\/h2>\n\n\n\n
What we know about GJ 887 d and its neighbors<\/h2>\n\n\n\n
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Why the habitable zone is only a first filter<\/h2>\n\n\n\n
A prime target for future life-hunting telescopes<\/h2>\n\n\n\n
The open questions scientists want to answer next<\/h2>\n\n\n\n
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