A team of astronomers has found evidence that two exoplanets orbiting a red dwarf star are “water worlds,” meaning planets that contain water make up a large part of their size, according to an RT report.
These two watery worlds, unlike any planets we see in our solar system, are located in a planetary system located 218 light-years from Earth in the constellation Lyra.
These planets are composed almost entirely of water, marking the first time these worlds have been confidently identified by scientists.
“We used to think that planets that were a little bigger than Earth were big balls of metal and rock, like expanded versions of our own Earth, which is why we called them ‘super-Earths’. However, it has now been shown that these two planets, Kepler-138c and Kepler-138d, are very different in nature: it is possible that a significant part of their volume is entirely made up of water.”
“This is the first time we have observed planets that can be confidently identified as water worlds, a type of planet that astronomers have long assumed existed,” he explained.
Scientists haven’t directly detected water, because it’s still hard from such a long distance. But investigations have shown that up to half of the planet is supposed to be made of something lighter than rock and heavier than hydrogen – and the most likely candidate for this material is water.
Both planets orbit the star Kepler-138, which is 218 light-years away and is located in the constellation Lyra.
It is estimated that each of the planets is about three times the size of Earth, and more than twice the mass of Earth – but much less dense than our planet.
Planets around Kepler 138 were first discovered in 2014, when they were observed using the Kepler Space Telescope, and they were found using the transit method, as scientists noticed the slight dip that occurs when planets pass in front of their star. .
The new study relied on further observations from NASA’s Hubble and Spitzer Space Telescopes, which allowed scientists to determine the planet’s composition. This additional data led scientists to believe that the two planets were actually from water worlds.
Scientists have explained that water worlds do not look like the usual classic planet we can imagine, with a surface that looks like the surface of the oceans on planet Earth in the first place. Instead, these planets are likely to be so hot that water instantly turns to vapor, creating a dense atmosphere that can hide liquid water.
Both planets are also outside the habitable zone, and since they are too hot for liquid water, they are likely uninhabitable. But new research also finds an additional planet in the system, known as Kepler-138e, located in the habitable zone.
This planet is smaller in size, far from its star, and its year takes 38 Earth days, but scientists are still not sure of its exact details, because it does not seem to pass in front of its host star.