Scientists discover 'best evidence yet' for 'water worlds'
| Last updated
Featured Image Credit: NASA Goddard/YouTube/NASA/ESA/Leah Hustak (STScI)
NASA's Hubble and Spitzer telescopes have found evidence that suggests two exoplanets orbiting a red dwarf star are 'water worlds'.
In case you're wondering, water worlds are where water makes up a large fraction of an entire planet - *pretends to be shocked*.
Perfect place to build a waterpark? Perhaps not.
These worlds are located 218 light-years away in the constellation Lyra and are unlike any planets found in our solar system.
The team led by of researchers at the University of Montreal published a detailed study of this planetary system, known as Kepler-138, in the journal Nature Astronomy.
Team leader Caroline Piaulet oversaw the whole project, which focused on observing exoplanets Kepler-138c and Kepler-138d with the help of NASA's telescopes.
Although the telescopes can’t directly observe the planets’ surfaces, analysis showed their densities were lighter than rock worlds but heavier than gas-dominated ones.
“Imagine larger versions of Europa or Enceladus, the water-rich moons orbiting Jupiter and Saturn, but brought much closer to their star,” explained Piaulet.
“Instead of an icy surface, they would harbor large water-vapor envelopes.”
Before you get your swimming trunks on, the two possible water worlds, Kepler-138c and d, are not located in the habitable zone, which is the area around a star where temperatures would allow liquid water on the surface of a rocky planet.
However, researchers actually found evidence for a new planet in the system, Kepler-138e, which happens to be in the habitable zone.
“We previously thought that planets that were a bit larger than Earth were big balls of metal and rock, like scaled-up versions of Earth and that’s why we called them super-Earths,” explained Björn Benneke, study co-author and professor of astrophysics at the University of Montreal.
“However, we have now shown that these two planets, Kepler-138c and d, are quite different in nature and that a big fraction of their entire volume is likely composed of water.
“It is the best evidence yet for water worlds, a type of planet that was theorized by astronomers to exist for a long time.”
Researchers also discovered that Kepler-138c and d are 'twin' planets, with virtually the same size and mass.
The planets were previously thought to be very different.
“As our instruments and techniques become sensitive enough to find and study planets that are farther from their stars, we might start finding a lot more of these water worlds,” Benneke concluded.