Artistic ilustration of planet K2-18b, its star K2-18 and the second planet K2-18. (CREDIT: www.alexboersma.com)
In a first, scientists have discovered water at a planet outside our solar system that has temperatures suitable for life. London researchers announced on Wednesday they have found water vapor in the atmosphere of a planet 110 light-years away. This so-called Super Earth is the right distance from its star to conceivably harbour life.
The University College London scientists say it's the only exoplanet known so far to have both water and temperatures needed for life, making it a prime candidate for potential life. But they caution it's not another Earth.
It's twice the size of Earth with eight times the mass, and its star is unlike our sun. No one knows if water's flowing on the surface. Lead author Angelos Tsiaras says it could help determine, "Is the Earth unique?"
The discovery, made with NASA's Hubble Space Telescope, serves as the first detection of water vapor in the atmosphere of such a planet. And because the planet, dubbed K2-18 b, likely sports a temperature similar to Earth, the newfound water vapor makes the world one of the most promising candidates for follow-up studies with next-generation space telescopes.
"This is the only planet right now that we know outside the solar system that has the correct temperature to support water, it has an atmosphere, and it has water in it, making this planet the best candidate for habitability that we know right now," Tsiaras said in a press conference. K2-18 b: The basicsPlanet K2-18 b sits some 110 light-years away in the constellation Leo, and it orbits a rather small red dwarf star that's roughly one-third the mass of our own Sun.
Red dwarfs are infamous for being active stars that emit powerful flares, but the researchers point out that this particular star appears to be surprisingly docile.This bodes well for the water-bearing planet, as its 33-day orbit brings it about twice as close to its star as Mercury is to the Sun. "Given that the star is much cooler than the Sun, in the end, the planet is receiving similar radiation to the Earth," said Tsiaras.