The Discovery of Iocaste
The moon, Iocaste is one of the latest moons of Jupiter to be discovered as part of a dedicated effort by researchers at the University of Hawaii’s Mauna Kea Observatory. Iocaste is one of many small moons discovered by a team headed by Scott S. Shepherd, David C. Jewitt, Yanga R. Fernandez, and Eugene Magnier. Iocaste was discovered on November 23, 2000, and was given the name S/2000 J3 upon its positive identification.
A Part of the Ananke group of moons
The moons of Jupiter are divided into two categories, those that formed naturally with the planet and those that were dragged into the mighty gravitational field of the planet. Iocaste falls into the second category because it has been group with 15 other satellites of Jupiter known as the Ananke group.
What is the Ananke group?
Iocaste is thought to be part of the Ananke group of Jovia moons orbiting the planet Jupiter at around the same distance from the surface and at similar angles to the equator of the planet. The largest moon in this group was given the name, Ananke and is thought to be the largest piece of an asteroid that was dragged into the orbit of Jupiter as it moved through our solar system. At some point, Ananke was involved in a collision with another object in space or in Jupiter’s orbit and shattered into much smaller pieces. The pieces of Ananke, including Iocaste, have since remained in orbit and are identified as moons with the same origin.
The Similarity to Other Ananke Group Members
One of the main ways astronomers group together different moons moving in similar orbits is by their coloring. Iocaste is a light gray color, which is the same as many of the other moons in the Ananke group. Similarities are thought to be most visible between Iocaste and the other Ananke moons of Praxidike and Harpalyke.
The Size and Shape of Iocaste
When most people think of a moon they imagine the spherical satellite swe see at night in our own sky. However, moons must be a certain size to be affected by the gravity of their parent planet to become spherical in shape. Iocaste only has a radius of 1.6 miles and is, therefore, too small to be affected by Jupiter’s gravity and take on the classic spherical shape. Although we do not know the exact shape of Iocaste, we do know the moon is not spherical and is classed as an irregular moon of Jupiter.
Iocaste is a retrograde moon, which means the satellite moves in the opposite direction to the spinning of Jupiter. This is a common feature of moons that originate from asteroids crashing into the orbit of Jupiter. All the 16 members of the Ananke group of moons, of which Iocaste is a member, move in a retrograde direction. The moon sits an average of 13.2 million miles from the surface of Jupiter but has an elliptical orbit meaning it moves closer and further away from the surface of Jupiter as it moves around the planet. In total, Iocaste takes 632 Earth days to complete a single orbit of Jupiter.
The Greek myth of Iocaste
Like the other moons of Jupiter, Iocaste got its name from a character in a Greek mythological story. In this case, Iocaste, often known as Jocasta, was a queen who gave birth to the legendary figure of Oedipus. Iocaste is also known by the name, Jupiter XXXIV.