The planet orbits within its star's habitable zone, which means it could hold liquid water on its surface - a key factor needed to sustain alien life.
This newly discovered exoplanet, named K2-18c, may be a second rocky super Earth - although it is unlikely to host alien life, scientists lclaim.
"Being able to measure the mass and density of K2-18b was tremendous, but to discover a new exoplanet was lucky and equally exciting", said Ryan Cloutier, a PhD student in University of Toronto Scarborough's Centre for Planetary Science. K2-18b, however, is now among the most exciting bets for atmospheric study.
As fascinating as this discovery that hints at the possibility of intelligent life beyond our blue ball may sound, the researchers also managed to locate another planet that neighbours the K2-18b, called K2-18c. K2-18b, scientists say, could be in an excellent location for alien life to emerge-having flawless conditions for surface water, a fundamental ingredient for life, to exist.
That is not all, the team of researchers, from the University of Montreal in Canada and the University of Texas in the United States, who conducted the study with data from the European Southern Observatory, also discovered that the planet has a neighbor. Scientists, aside from two regular signals that they received every 39 days from the star's rotation and every 33 days from the planet's orbit, discovered a third signal which they received every nine days, which was the first indication that there might be another planet close to K2-18b. The Harps tool measures the radial velocity of stars that is impacted by a planet's presence.
"It wasn't a eureka moment because we still had to go through a checklist of things to do in order to verify the data", Cloutier said.
The dataset used by Cloutier, the lead author, and other researchers came from the High Accuracy Radial Velocity Planet Searcher (HARPS) using the ESO's 3.6-metre telescope at La Silla Observatory, in Chile.
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, ' Mr Cloutier said.
"It was while looking through the data of K2-18b that we noticed something unusual", he said.
At present, the scientists are not able to distinguish between the two options; however, they feel more data can be collected with the help of the James Webb Space Telescope. After figuring out the mass measurements of the planet, the team of researchers successfully established the fact that K2-18b is either largely a water planet with a thick ice-layer over it or it is essentially a rocky planet with a compact atmosphere full of gases, just like that of Earth, but larger in size.