Discovery of Moons
American astronomer Seth Barnes Nicholson discovered Carme at the Mount Wilson Observatory in California in July of 1938. The Illinois native previously discovered the moons now named Mildred, Menelaus, and Sinope before his discovery of Carme. The astronomer also receives credit for the later discovery of the moons Lysithea and Ananke. Nicholson did not name Carme, referring to it at the time as Jupiter XI.
Receiving a Name
From 1955-1975 some scientists referred to Jupiter XI as Pan. In 1975 the moon received the formal name of Carme, after a Cretan goddess. The goddess was the parent, along with Zeus, of Britomartis. The god Zeus is the Greek equivalent of the Roman god Jupiter. Since 1973 the International Astronomical Union (IAU) requires all moons to have the name of a relative or lover of the God the planet shares its name with.
The IAU committee for Planetary System Nomenclature has the task of selecting a name for each moon. The committee gives a “e” ending whenever a body orbits in retrograde. The definition of retrograde is to move backward, and in this instance, it refers to when an orbiting body moves in the opposite direction of the planet it circles. Carme orbits Jupiter in retrograde.
Description of Carme
The diameter of Carme is 18.5 miles and it has a mass of 9 x 1016 kg (about 10 tons). It takes around 734 Earth days for Carme to orbit Jupiter. The moon is light red and is around 13-14 million miles away from Jupiter. Carme is not visible from Earth with most telescopes.
The Carme Group
The Carme group is a collection of bodies that orbit Jupiter in retrograde with Carme. Scientists believe that the group was once a single asteroid that broke into pieces during an impact. The pieces became captured by Jupiter’s gravity and remain in orbit today. Most of the mass of the original body remains with Carme.
The Carme group are retrograde irregular satellites that are all smaller than Carme. Each satellite’s name follows the IAU rule of relating to Zeus. The names were all given between the years 2002-2019. Each satellite has a similar light-red color as Carme except Kalyke which is much redder than the others. The named satellites in the group include;