Science

K2-18b: 'Super-Earth' That Could Host Alien Life Is Discovered

K2-18b: 'Super-Earth' That Could Host Alien Life Is Discovered

The lead author Ryan Cloutier, from the University of Montreal, stated that being able to cover the mass and density of K2-18b was enormous but to find a new exoplanet was fortunate and equally exciting.

The distant exoplanet is known as K2-18b and has been described as being a potential "Super-Earth" - a large rocky planet with the potential to support life. This solid planet which could be a scaled up version of Earth revolves around its star in the comfortable zone that indicates that it may be covered in liquid water and can be a planet with alien life.

The large rocky exoplanets were discovered using data collected by the European Southern Observatory's HARPS instrument.

The astronomers found that K2-18b has a mass about 8 times that of Earth. Dubbed K2-18c, the planet is also a Super Earth, though because of its proximity to its star it's not likely that liquid water could exist on its surface, which makes it a lot less appealing to humans.

They orbit a red dwarf star 111 lightyears away - or 625,000,000,000,000,000 miles away - in the Leo constellation.




"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 noted. The High Accuracy Radial Velocity Planet Searcher (HARPS) planet-finding spectrograph installed on the telescope measures the radial velocities of stars, which are affected by any nearby planets, with the highest accuracy available, enabling it to detect even the smallest of planets. "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. They measured radial velocities of stars, which can reveal the existence of planets located around the measured stars.

"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", says Cloutier.

"With the current data, we can't distinguish between those two possibilities", Cloutier added. K2-18b offers a unique chance for research when NASA's James Webb Space Telescope will launch in 2019.

They found that the planet is probably mostly rocky with a gaseous atmosphere - like Earth, only bigger - however it may be a mostly water planet with a thick layer of ice, so further investigation is needed.

It was while looking through the data of K2-18b that Cloutier noticed something unusual. In addition to two regular signals - one every 39 days from the star's rotation and the other every 33 days from the planet's orbit - the researchers found a third signal occurring every nine days. "But whether or not there is surface water, we're going to have to do some follow up observations to figure that out for sure, because right now we just don't know".