Which planet in the solar system has the moon Pandora orbiting it in the movie Avatar?

Pandora is a small moon of Saturn discovered by Voyager 1 in 1980. It is about 100 kilometres in diameter, without an atmosphere and nothing like the one depicted in the movie Avatar. That Pandora is a fictional lush, Earth-like moon of the fictional planet Polyphemus in the Alpha Centauri star system.