The Courier & Advertiser (Perth and Perthshire Edition)
Analysis reveals super-Earth has potential to support life
Exoplanet in habitable zone 110 light years away has water vapour
Scientists in the UK have made a “world first” discovery on a distant planet that hosts both water and temperatures which could support life.
Water vapour has been detected on a potentially habitable super-Earth known as K2-18b, located about 110 light years away.
The exoplanet was first spotted in 2015 by Nasa’s Kepler spacecraft but analysis of data has revealed new details that have not been seen on a superEarth before.
K2-18b is classed as a super-Earth because it is bigger than our Earth – twice as big in fact, as well as eight times heavier.
Current equipment is only able to determine basic factors such as distance, mass and temperature but sophisticated tools developed at University College London have been able to translate existing data from the Hubble Space Telescope to make sense of the unique molecule signatures of water vapour.
K2-18b is too far away for astronomers to see, but they can look at how starlight is filtered through the planet’s atmosphere as it passes around its own sun, called K2-18.
The planet is a lot closer to its star than Earth is to the Sun, meaning it only takes around 33 days to transit.
“It’s the only planet outside our solar system that we know has the correct temperature, an atmosphere and water,” said first author Dr Angelos Tsiaras.
“Of course, K2-18b is not a second Earth, because it is a planet that is much bigger, has a different atmospheric composition. It’s orbiting a different star, so it doesn’t look like Earth.”
Although the planet sits in the habitable zone, scientists say that instruments available at present are not able to determine any signs of life. It will also require many more observations to be sure it is a habitable planet.