Scientists find first 'super-Earth' with water that is inside the habitable zone

Scientists have discovered a planet outside our solar system with water and temperatures that can support life.

The memorably named “K2-18b” has eight times the mass of Earth and is about 110 light years away, in the Leo constellation.

It is the first time another planet has been found orbiting a star’s habitable zone – ie, where water can exist in liquid form.

First author of the study Dr Angelos Tsiaras, from University College London, explained: “Finding water in a potentially habitable world other than Earth is incredibly exciting.

“K2-18b is not ‘Earth 2.0’ as it is significantly heavier and has a different atmospheric composition. However, it brings us closer to answering the fundamental question: Is the Earth unique?”

To identify the planet, the team used archive data from 2016 and 2017 captured by the ESA/NASA Hubble Space Telescope.

Future studies could help them estimate the planet’s cloud coverage and its percentage of atmospheric water.

Because the planet’s star, K2-18, is a highly active red dwarf, it is believed K2-18b could be much more hostile than Earth.

The planet was first discovered in 2015.

“With so many new super-Earths expected to be found over the next couple of decades, it is likely that this is the first discovery of many potentially habitable planets,” Dr Ingo Waldmann, also from University College London, said.

“This is not only because super-Earths like K2-18b are the most common planets in our galaxy, but also because red dwarfs – stars smaller than our Sun – are the most common stars.”