Astronomers looking for signs of life beyond our solar system have discovered three habitable planets just 40 light years away. They orbit a dim dwarf star located in the constellation Aquarius. The discovery could significantly boost the chances of finding alien life forms, said astronomers. Findings of the study were published Monday in the journal Nature.
An accidental discovery of potentially habitable planets
The planets are located at a distance from their host star that provides the right amount of heat for them to harbor liquid water on their surface. Astronomers believe liquid water is necessary to foster life as we know it. The ultra-cool dwarf star supports the hypothesis that even low-temperature and low-mass stars could have Earth-sized planets orbiting them. The newly discovered planets are the size of Venus and Earth.
Lead researcher Michaël Gillon of the University of Liege in Belgium said, “If we want to find life elsewhere in the universe, this is where we should start to look.” Notably, the habitable planets were discovered by accident. Astronomers were conducting a test survey of an ultra-cool dwarf star called TRAPPIST-1 located in the constellation Aquarius.
They were preparing for a much bigger project that will commence later this year, with the help of a larger telescope. The test survey was meant to assess the feasibility of the project. But the relatively smaller Transiting Planets and Planetesimals Small Telescope, or TRAPPIST, worked so well that it “detected an amazing system around a nearby ultra-cool dwarf.”
The third planet is in the Goldilocks Zone
Though the planets are about the size of the Earth, their parent star is only 8% the size of our sun. And it is less than 0.5% as bright as the sun. Two of the habitable planets orbit the dwarf star within 1.1 to 1.5% of the distance between Earth and the sun. Gillon says the star is faint, small and cold, so it emits much less photons. As a result, the temperature on these planets should be similar to that of Venus.
The third planet is further away from the star. Researchers estimate that it passes in front of the dwarf star every four to 72 days. This planet falls in the Goldilocks Zone of habitability, meaning its temperature should be similar to that on Earth.