The Discovery of Helike
A concerted effort was made by a team of astronomers at the University of Hawaii to explore the objects moving through the orbit of Jupiter. The team was headed by astronomer Scott S. Shepherd and worked from a base at the Mauna Kea Observatory where a number of years were spent exploring the possible moons of the planet. Helike was discovered by Shepherd’s team on February 6, 2003, and given the classification S/2003 J6.
Orbiting Jupiter
The moon of Helike is found in an eccentric orbit moving around the planet of Jupiter, meaning the orbit of the moon is not circular but an oval shape around the planet. Helike is known as a retrograde orbiting moon, which means it moves in the opposite direction to the movement of Jupiter as it travels around the Sun. In terms of distance from the surface of Jupiter, the orbiting of Helike takes place a long way from the planet at around 13.1 million miles from the surface. The large size of Jupiter and the limited size of the moon means the orbit of the moon takes around 626 Earth days to complete its movement around the planet.
A member of the Ananke group of moons
There are 16 moons in the Ananke group that orbit the planet in similar orbits and at similar speeds. The fact these 16 moons share a number of characteristics allows them to be classed as coming from the same origin. It is not thought the Ananke group of moons, including Helike were formed at the same time as Jupiter itself. Instead, most astronomers agree that a large asteroid was sucked into the orbit of Jupiter and has remained there ever since. At some point, the asteroid is thought to have collided with another object either in the orbit of Jupiter or before it was captured forming a group of smaller moons. Helike is theorized to be one of the smaller moons forming from the larger asteroid, which remains in the orbit of Jupiter as Ananke.
The Characteristics of Helike
The Helike moon is not a large object in the orbit of Jupiter measured at around 1.2 miles in radius. As part of the Ananke group of moons, Helike is not large enough to have its natural shape affected by the gravity of Jupiter and the solar blasts originating from the Sun. Helike moves through ots orbit of Jupiter at a speed of over 5,000 miles per hour and has a gravity estimated by astronomers at around 0.002. The speed needed for an object to escape the gravity of Helike is measured as its escape velocity with an object moving out of Helike’s atmosphere needing to travel at just five miles per hour.
The Naming of Helike
The moons of Jupiter have traditionally been named after the characters from Greek mythology to keep them grouped together and understandable for astronomers. Helike gets its name from a number of female characters described throughout the stories of ancient Greece. One of the most famous characters known as Helike is a nurse who cared for the infant Zeus throughout his childhood. Often seen as a nymph in the ancient Greek literature, Helike is usually described as being transferred to the stars as a reward for her work caring for Zeus. The name Helike was officially given to the moon in March 2015, with the position as the fifth, argest moon in the Ananke group reflected in the alphabetical position of the name in the list of the group’s names.