super-earth
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Recently a new research has revealed that an exoplanet, named K2-18b, could very well be a larger version of our home planet Earth and it also has excellent possibilities of harboring alien life. The same researchers also found out that this planet is not alone there; in fact, it has a neighbor. They used European Southern Observatory's (ESO) findings and data to reach the conclusion.

"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 the lead author of the study Ryan Cloutier, who is a PhD student in the Department of Astronomy, Université de Montréal Institute for research on exoplanets (iREx) and Scarborough's Centre for Planet Science and Astrophysics. 

The researchers discovered that K2-18b, which is now being called super-Earth, and its neighbor planet, both orbit a red dwarf star, named K2-18, which is situated in the constellation Leo, around 111 light years away from Earth, reported UdeMNouvelles - Université de Montréal

K2-18b was first spotted by the astronomers in 2015. At that time they noticed that the super-Earth was orbiting the dwarf-star within its habitable zone. Now the researchers have exhausted the data set collected by the High Accuracy Radial Velocity Planet Searcher (HARPS). HARPS used the 3.6m telescope of ESO at La Silla Observatory, in Chile to gather that data.

To determine whether K2-18b was a scaled-down version of Neptune, composed largely of gas, or a scaled-up version of Earth, made up mostly of rock, researchers first had to find out the mass of the planet, making use of the radial velocity measurements data gathered by HARPS. 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.

"With the current data, we can't distinguish between those two possibilities. But with the James Webb Space Telescope (JWST) we can probe the atmosphere and see whether it has an extensive atmosphere or it's a planet covered in water," said the lead author. As per the researchers, the James Webb Space Telescope (JWST) will play a significant role in finding out further information about this super-Earth. The telescope is scheduled to be launched in 2019.

Also Read: How does Earth sound to aliens? You will be knowing soon!

The newly discovered neighbor of K2-18b is the K2-18c, which is another super-Earth, meaning its mass is also similar to that of the Earth. However, K2-18c doesn't really have a favourable atmosphere for life to thrive in it, as it's much closer to its star, being too hot to be habitable.

"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. Once all the boxes were checked it sunk in that, wow, this actually is a planet," said Ryan Cloutier, who had the target of finding at least one new exoplanet during the course of his Ph.D.