With more than 3,000 exoplanets confirmed by NASA at this point, you might wonder what's so special about finding another one-but it's an incredibly rare phenomenon to confirm an exoplanet, let alone to find two super-Earths sitting right next to each other light years away from Earth.
Renewed interest in K2-18b after its initial discovery is the result of new research that determined the planet was both larger than Earth, and likely rocky, which is enough to classify it as a "Super Earth".
As for the neighbouring planet K2-18c, the researchers concluded that it was quite close to the sun and therefore uninhabitable due to high temperatures, but like the K2-18b it is also a Super-Earth.
Just last month, space boffins said they had found another "Super Earth". They also found for the first time that the planet has a friend, named K2-18b. When we finally decide to make the move, a planet called K2-18b might be our destination. They found the planets circling the red dwarf star K2-18, which is part of the constellation, Leo. Since K2-18b is likely rocky, this means the planet could have liquid water on its surface, which is one of many conditions for supporting life.
The study by researchers at the University of Texas and the University of Montreal was carried out using data from the European Southern Observatory (ESO).
Using sophisticated machine-learning techniques, the team figured out the planet could well be an Earth-like planet made mostly of rock and with a gaseous atmosphere.
"If you can get the mass and radius, you can measure the bulk density of the planet and that can tell you what the bulk of the planet is made of", said Ryan Cloutier, a Ph.D. student at the University of Toronto, Canada, and who was the lead author of the research, in a statement published on Tuesday. However, scientists weren't sure whether the planet had a rocky or terrestrial surface like Earth or if it was more like a Neptune kind of planet, which consists of gas and ice.
By collecting so-called "radial velocity" data on K2-18, the scientists were able to estimate the size of K2-18b.
Engineers inspect the James Webb Space Telescope after cryogenic testing in Houston, November 19, 2017. After ruling out the possibility of noise, the astronomers announced a second planet called K2-18c.
The next step, according to Cloutier, will be to probe the atmosphere for the presence of water with the help of the James Webb Space Telescope, the NASA/ESA/CSA telescope expected to be completed and launched in two years' time.
Study co-author Professor René Doyon, also from the University of Montreal, added: "There's a lot of demand to use this telescope, so you have to be meticulous in choosing which exoplanets to look at".
"When we first threw the data on the table we were trying to figure out what it was".