It’s possible. For example, in November 2007 a planet was discovered around the star 55 Cancri that appears to be orbiting in the habitable zone. This planet is almost certainly a gas giant planet and not a terrestrial one—its minimum mass is about twice the mass of Neptune. But like the gas giants in our solar system, it may have moons orbiting it that may have rocky or metallic crusts and mantles. Those moons, if they exist, could harbor liquid water. Thus, with its host star providing just the right amount of heat and light, such a moon could harbor life as well.