The Exoplanet K2-18b is a super-Earth that doubles the size of our planet, with eight times its mass. It is also very wet, or at least in the sky around it. Researchers found evidence of water vapor when they collected data obtained by NASA'sin 2016 and 2017 and ran it through an open-source algorithm they developed to study distant planets. They published their findings Wednesday in the journal Nature.
Water vapor is found in the atmospheres of other planets, but this is the first time that such moisture has been detected on a planet in its star zone of residence, where temperatures can be tolerant, if not very pleasant.
A lot of data is needed to determine what kind of cloud is covered by the planet, how much water is in the atmosphere and whether things actually form large bodies of water on the surface of the planet like here on Earth.
"It's entirely possible that this is a world of water," said co-author Giovanna Tinetti, a professor of astrophysics at University College London. But he warned that it was too early to confirm the existence of some kind of sea.
It is estimated that temperatures on the planet can be between minus 100 degrees Fahrenheit (minus 73 Celsius) and 150 Fahrenheit (66 Celsius). That's a huge scope, of course, but not too far from the conditions we see here on Earth.
"However, this planet is not a second Earth," Angelos Tsiaras, an associate professor at UCL, told reporters on Tuesday. "Withdrawing what we call a red dwarf star … in this environment the space age is much warmer than it is on Earth."
also called M-dwarf stars, are. smaller, cooler and deeper than our day. They are also known for frequent releases of strong solar flares that may . Fortunately, the K2-18, 110 light years from Earth, is not susceptible to other M-dwarf stars.
"This particular one is not very active," Ingo Waldmann, a lecturer in extrasolar planets at UCL and co-author of the paper, told me. "We didn't see anything burning."
Starlight analysis passing through the planet's atmosphere also revealed hydrogen and helium. Future studies could determine whether other molecules closely related to life as we know it, such as nitrogen and methane, are also present.
Researchers expect the upcomingto be significantly more powerful than Hubble, may provide a clearer view of what is happening to distant exoplanets. If the conditions are right, you can also add K2-18b to an interstellar travel itinerary in the distant future.
"Our discovery makes K2-18b one of the most interesting targets for future study," Tinetti said.
Originally published Sept. 11, 10 a.m. PT.