Phoebe orbits Saturn at a distance of 8,049,668 miles (12,952,000 kilometers) from Saturn - almost four times the distance of its nearest neighbor, Iapetus - and it completes a full orbit around Saturn in about 550 days. Phoebe and Iapetus are the only major moons in the Saturnian system that do not orbit closely to the plane of Saturn's equator. Phoeboe's orbit is inclined about 30 degrees to Saturn's equator. In addition, Phoebe's orbit is retrograde - it goes around Saturn in the opposite direction from Saturn's other large moons.
Phoebe is roughly spherical, and has a diameter of about 220 kilometers (about 132 miles), and rotates on its axis every nine hours. Unlike most of Saturn's major moons, Phoebe's surface is very dark, and reflects only 6 percent of the sunlight it receives. Its dark surface and irregular, retrograde orbit suggest that Phoebe is most likely a captured Centaur asteroid or Kuiper Belt object from the outer solar system.