http://www.newsweek.com/exoplanets-habitable-moon-gas-giants-951311

Scientists have identified just 50 or so potentially habitable bodies among thousands of confirmed exoplanets. These rocky orbs are less than twice the size of Earth and lie within the so-called Goldilocks zone of a star, where they’re not too hot and not too cold, but just right for liquid water.

Now, researchers have turned to gas giants in the search for habitable celestial bodies. Although these Jupiter-like planets aren’t candidates for life, their rocky moons could be.