Sycorax (moon)

Sycorax is the largest irregular moon of the planet Uranus. It measures about 157 kilometers across. Sycorax was discovered on September 6, 1997, using the Hale Telescope in California. Unlike most of Uranus's moons, Sycorax travels in a backward, uneven path around the planet and stays much farther away. Scientists think Sycorax may have been captured by Uranus's gravity rather than forming together with the planet.

Discovery and Naming

Sycorax was found by scientists using the 200-inch Hale Telescope, along with another moon called Caliban. At first, it was called S/1997 U 2. Later, it was officially named Uranus XVII after Sycorax, who is Caliban's mother in William Shakespeare's play The Tempest. This naming fits the pattern of naming all of Uranus's moons after characters from Shakespeare's plays or Alexander Pope's The Rape of the Lock.

Orbit

Sycorax has a very far orbit around Uranus, more than 20 times farther out than the farthest regular moon, Oberon. Its orbit goes in the opposite direction and is tilted and stretched out. Scientists think Sycorax might share a similar origin with two other moons, Setebos and Prospero, but Sycorax looks different because it has a much redder color than the others, which are usually gray.

The picture shows the paths of the moons that orbit Uranus backward, with lines showing how stretched out their paths are.

Physical characteristics

Sycorax is one of the biggest moons around Uranus. It is about 157 kilometers wide, which makes it the largest of Uranus's unusual moons. It looks a light-red color when seen with visible light.

We think Sycorax turns once every about 7 hours. We do not know exactly where its north pole points, but we have some ideas about its position.

Origin

Scientists think Sycorax may have been captured by Uranus instead of forming there naturally. Exactly how this happened is not known, but it likely needed some way to lose energy. Possible ways include getting slowed down by gas around the young Uranus or interactions with many other objects.

Exploration

Sycorax has not been seen up close by a space probe. Since it was found, scientists have only studied it using telescopes from Earth.