Extrasolar planet. Computer artwork of a planet orbiting a binary system of red dwarf stars. A red dwarf is smaller and cooler than our own Sun, emitting little light. Red dwarf stars are the most numerous form of star in the universe. An Earth-like planet orbiting a red dwarf may sustain life if it is close enough to obtain sufficient solar energy. At this close distance however, the planet becomes tidally locked and does not rotate, creating a world that is perpetually light and hot on one side, and dark and frozen on the other side. The optimum conditions for life would exist in the narrow region between night and day.