Astronomers have discovered a system of seven Earth-sized exoplanets orbiting a nearby star, at least three of which sit in the star’s temperate “habitable zone,” where liquid water could exist.The proximity of the planets’ host star, known as TRAPPIST-1, to our own — it lies just 39 light years away — immediately rockets this system to one of the best places to look for life outside our own solar system.A Canadian instrument aboard the James Webb Space Telescope, a next-generation space telescope set to launch next year, will be positioned to do just that. “We’re very excited here in Canada,” says Université de Montréal professor René Doyon, the principal investigator of the instrument, NIRISS, which is provided to the project by the Canadian Space Agency.“We will be among the first to actually study these habitable-zone exoplanets,” Doyon said.(An exoplanet is a planet that orbits a star outside the solar system.)TRAPPIST-1 is a small, ultra-cool dwarf star. Because the planets all orbit very close to it — the orbital periods of the six innermost planets range from 1.5 to just more than 12 days — those six at least could have surface temperatures between zero and 100 degrees Celsius.Initial estimates of the masses of the six planets suggest they could be similar to Earth’s, and the planets are likely terrestrial.At least three sit in the habitable “Goldilocks” zone, the region where water could be discovered, and, therefore, where life could theoretically exist.“It’s the first time that so many planets of this kind are found around the same star. They form a very complex system,” says Michaël Gillon, an astronomer at the Université de Liège in Belgium and lead author of a paper announcing the discovery, published in the journal Nature. In one sense, the discovery of the planets is not a surprise; bef ...
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