London:  Astronomers hunting for rocky planets with the right temperature to support life estimate there may be tens of billions of them in our galaxy alone.

A European team said yesterday that about 40 per cent of red dwarf stars — the most common type in the Milky Way — have a so-called "super-Earth" planet orbiting in a habitable zone that would allow water to flow on the surface.

Since there are around 160 billion red dwarfs in the Milky Way, the number of worlds that are potentially warm enough and wet enough to support life is enormous.

Xavier Bonfils of the Institute of Planetology and Astrophysics in Grenoble, the leader of the team, said the 40 per cent figure was at the high end of what had been expected and the finding underscored the prevalence of small rocky planets.

His team is the first to calculate the number of super-Earths — planets with a mass between one and ten times the Earth — in such habitable zones, although previous research has found the Milky Way to be awash with planets.