Achilles is a gas giant type of planet with a size comparable to a size somewhere between Saturn and Neptune-size, about 1.7 times as dense as water, with a strong equatorial bulge. In appearance, it is a dark, yellow-biased red, with scattered orange patches indicating storm systems. Achilles has several moons. Several of its moons have no information known about them that are not listed here, such as one within the orbit of Neoptolemus, four between that and Ulysses, and twenty outside of Ulysses'; all of these others are captured asteroids.

Community content is available under CC-BY-SA unless otherwise noted.