A European team said on Wednesday that about 40 percent 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 percent figure was at the high end of what had been expected and the finding underscored the prevalence of small rocky planets.