Life may have evolved on at least three planets in a newly discovered solar system just 39 light years from Earth, scientists believe.
Astronomers have detected no less than seven Earth-sized worlds orbiting a cool dwarf star known as TRAPPIST-1.
The six inner planets lie in a temperate zone where surface temperatures range from zero to 100C.
Of these, at least three are thought to be capable of having oceans, increasing the likelihood of life.
No other star system known contains such a large number of Earth-sized and probably rocky planets.
British astronomer Dr Chris Copperwheat, from Liverpool John Moores University, who co-led the international team, said: "The discovery of multiple rocky planets with surface temperatures which allow for liquid water make this amazing system an exciting future target in the search for life."
A robotic telescope operated by Liverpool John Moores University played a major role in the discovery reported in the journal Nature.
It was one of a number of ground-based instruments that supported observations made by American space agency Nasa's orbiting Spitzer telescope.
The Liverpool telescope helped detect the planets as they passed in front of their star.
Dr Copperwheat said: "As a robotic telescope and the largest in the world, the Liverpool telescope is very sensitive to the small, less-than-1% dips in brightness through which the planets are discovered. It's all automated, it's flexible and fast, and so is ideal for this sort of time critical work."
The planets were found using the "transit" method that looks for tiny amounts of dimming caused by a world blocking light from its star.
The Liverpool Telescope is located on La Palma in the Canary Islands
