In an unexpected surprise, while researching the behavior of K2-18b, astronomers noticed something that they thought might have been signal noise but eventually determined was an entirely new planet orbiting K2-18 much closer than K2-18b does.
"And so we sort of know that, for this planet, it's got about the right temperature that it could have liquid surface water".
To make the groundbreaking discovery, Cloutier first had to learn the planet's mass by using radial velocity measurements to determine if K2-18b was a rocky planet with liquid water similar to Earth, or a mostly gaseous planet like Neptune.
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.
SCIENTISTS have discovered a supersized version of Earth that could host life on a distant galaxy. Both the planets revolve around the red-dwarf star K2-18, which is 111 light years from Earth.
In the search for extraterrestrial life, scientists conducted new research which suggests that the exoplanet K2-18b could have a Super-Earth neighbor.
Using data collected by the European Southern Observatory, researchers from Canada's University of Toronto and Université de Montréal were studying the mass and density of the little-known planet K2-18b, which was discovered back in 2015. To do so, researchers used the La Silla Observatory in Chile, pulling data sets from the High Accuracy Radial Velocity Planet Searcher (HARPS), which can detect even very tiny planets that surround stars. HARPS allows for measurements of radial velocities of stars, which can be affected by the presence of nearby planets, to be taken with the highest accuracy now available.
"With the current data, we can't distinguish between those two possibilities", Cloutier added. "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".
Researchers have found that K2-18b could be a scaled-up version of Earth.
JWST is NASA's successor to the Hubble Space Telescope and is now scheduled to be launched in spring 2019. 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.
"Once all the boxes were checked it sunk in that, wow, this actually is a planet", he said.
"When we first threw the data on the table we were trying to figure out what it was".
The newly discovered planet is closer to its star, meaning it is likely to be too hot to support life.