At 40 light-years away, the TRAPPIST-1 star system is the closest solar system to Earth that has been discovered.
The solar system was discovered in February by Nasa which found seven planets orbit the relatively dim star.
The newly-discovered solar system has attracted the interest of alien hunters as three of its planets fall into the star’s habitable, or “goldilocks”, zone – the region around a host star where conditions are neither too hot nor too cold to support life.
Now, an international team of researchers who have been studying images of TRAPPIST-1 and its planets from the Hubble Telescope and found three of the planets could have water on the surface.
By analysing images of the planets, the scientists were able to determine how much free-floating hydrogen was in the atmosphere and how intense the star’s Ultra Violet radiation is. The weaker it is, the more likely that water could be on the planets.
Team leader Vincent Bourrier from the Observatoire de l’Université de Genève explained: “Ultraviolet radiation is an important factor in the atmospheric evolution of planets.
“As in our own atmosphere, where ultraviolet sunlight breaks molecules apart, ultraviolet starlight can break water vapour in the atmospheres of exoplanets into hydrogen and oxygen.”
Their research revealed that the first three planets receive too much UV radiation from the star, and calculations suggest they would have lost 20 Earth’s worth of water during their eight billion year history.
But the remaining outer planets, while still receiving a high amount, “should have lost much less water, suggesting that they could have retained some on their surfaces”, according to a statement from the European Space Agency (ESA).
Further research will now be conducted, according to Dr Bourrier who said: “While our results suggest that the outer planets are the best candidates to search for water with the upcoming James Webb Space Telescope, they also highlight the need for theoretical studies and complementary observations at all wavelengths to determine the nature of the TRAPPIST-1 planets and their potential habitability.”