Water-rich exoplanets common outside earth's solar system: Study

Water-rich planets are very common outside our solar system and water is one of the major components of exoplanets between two to four times of the size of earth, according to a new study that also hints at life in our galaxy.

A research based on the data from the exoplanet-hunting Kepler Space Telescope and the Gaia mission indicated that most of such planets may contain water as much as 50 per cent or more.

"It was a huge surprise to realise that there must be so many water-worlds," Li Zeng, a researcher of Harvard University in the United States said.

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Researchers have discovered that many of the exoplanets scientists have discovered so far are of two categories – one with an average planetary radius around 1.5 that of the earth and another around 2.5 times the radius of the earth.

They have developed a model of their internal structure after studying the based on the studies of the exoplanets with mass measurements and recent radius measurements from the Gaia mission.

“The model indicates that those exoplanets which have a radius of around x1.5 Earth radius tend to be rocky planets (of typically x5 the mass of the Earth), while those with a radius of x2.5 Earth radius (with a mass around x10 that of the Earth) are probably water worlds," Zeng said.

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He said that the data indicated that 35 per cent of the all known exoplanets were bigger than the earth and may be rich in water.

"Our data indicate that about 35 per cent of all known exoplanets which are bigger than Earth should be water-rich," Zeng added.