Exoplanet searchers published a paper on Thursday in the journal Nature Astronomy stating that we have now added another alien globe to our reserve.
Scientists have found two exoplanets that appear to be coated in sheets of none other than water, the elixir of life, using NASA’s orbiting Hubble and retired Spitzer Space Telescopes.
These blue spheres, Kepler-138 c and Kepler-138 d, circle a faint red dwarf star 218 light-years distant in a solar system. They are about 1.5 times as huge and nearly twice as hefty as Earth. These measurements suggest that the Kepler pair are distantly related to one another on Earth, which makes the narrative of the Keplers seem weirdly incongruous.
The co-author of the study and University of Montreal professor Björn Benneke stated in a statement that “we previously assumed that planets that were a little larger than Earth were enormous balls of metal and rock, like scaled-up replicas of Earth.”
In reality, Kepler d is still listed as a “potentially rocky” world in NASA’s online Exoplanet Catalog, for instance.
But as Benneke pointed out, “we have now demonstrated that these two planets, Kepler-138c, and d, are fundamentally different in nature: a large fraction of their entire volume is undoubtedly formed of water.”
Overall, this is the first time that exoplanets have been unambiguously identified as water worlds. Astronomers have long theorized about this type of planet, but it hasn’t been conclusively proven.
It’s vital to remember that, contrary to popular belief, these so-called water worlds are not expected to have seas.
“We predict a thick, dense atmosphere made of steam on these planets,” said Caroline Paulet, team leader and Ph.D. student at the University of Montreal, in a release. “The temperature of Kepler-138c’s and Kepler-138d’s atmospheres is likely over the boiling point of water.”
According to Monisha Ravisetti from CNET, high-pressure liquid water or even water can only exist in a distinct phase known as a supercritical fluid when there is a steam environment present.
Researchers claim that the Kepler twins are more like larger versions of Europa or Enceladus, i.e., water-rich moons that currently circle Jupiter and Saturn, but much nearer to their star.
Paul claims that Kepler-138 c and d “would maintain large water vapor envelopes instead of an ice surface.”
Technically, both of the studied exoplanets had already been found by NASA’s Kepler Space Telescope (thus their names), but it wasn’t until recently that scientists believed they had conclusive proof of the spheres’ composition. They previously established that Kepler-138 b, a different member of the Kepler 138 red dwarf system, is a terrestrial planet with a mass of 0.0066 Earth, but they still needed further information for c and d.
Despite the fact that water was not directly discovered, the researchers were nonetheless able to utilize these NASA telescopes to compare the sizes and masses of the planets to models that projected up to 50% of the volume of these worlds.