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

K2-18b and its neighbour newly discovered K2-18c orbit the red-dwarf star k2-18 locataed 111 light years away in the constellation Leo

It appeared to be a super-Earth, a rocky planet more massive than Earth, but Kepler couldn't tell us for sure.

K2-18b's newly found super-Earth status comes after a slew of other recent, rocky planet-related discoveries. The planet is also a super-Earth, but likely orbits too close to its parent star to have liquid water on its surface.

Researchers at the Centre for Planetary Sciences have found that K2-18b could very well be a scaled-up version of Earth.

In the case of K2-18b, astronomers began observing it with the European Southern Observatory's planet-hunting HARPS instrument, which is part of the 3.6-meter telescope in the La Silla Observatory.

Trying to find out whether the planet is more like a scaled-down version of Neptune made mostly of gas, or a scaled-up version of Earth made mostly of rock, the researchers used radial velocity measurements of its star, and a machine learning calculator. On top of this, the team also discovered that this planet-K2-18b-has another, similar world hiding behind it. But it is by studying its mass recently that an global team of scientists has learned that this planet was not only potentially habitable, but that it had also a neighbour.

"Being able to measure the mass and density of K2-18b was tremendous, but to discover a new exoplanet was lucky and equally exciting", lead author Ryan Cloutier, an astronomy and astrophysics Ph.D. student at the University of Toronto and the University of Montreal's Institute for Research on Exoplanets, said in a statement. Radial velocities can reveal slight wobbles caused by the pull of an exoplanet's gravity on its host star.

The researchers surmised that K2-18b has a mass between six and 10 times that of Earth, making it either mostly rocky with a small gaseous atmosphere or a mostly water planet with a thick layer of ice on top.

An global team of astronomers has found that a little-known exoplanet called K2-18b could be a scaled-up version of Earth, and also discovered the planet has a massive neighbor, K2-18c.

Current technology prevents us from being able to definitively say which one it is but the fact that it could be either is a huge leap forward in our understanding of this distant solar system.

The researchers say K2-18b will be a prime target for Nasa's James Webb Space telescope, which will search for planets with habitable atmospheres, when it launches in 2019. The space telescope is geared toward obtaining a range of data to help scientists study the solar system, exoplanets, and the early universe.

It was while looking through the data of K2-18b that Mr Cloutier noticed odd signals, which the researchers realised was a second exoplanet.

René Doyon, Cloutier's co-supervisor and a co-author of the paper published Tuesday in the journal said the next step will be to determine the atmosphere of K2-18b, since it's the most promising candidate for sustaining life.

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