Io (moon) - Nomenclature

Nomenclature

See also: List of regions on Io, List of volcanic features on Io, and List of mountains on Io

While Simon Marius is not credited with the sole discovery of the Galilean satellites, his names for the moons were adopted. In his 1614 publication Mundus Iovialis anno M.DC.IX Detectus Ope Perspicilli Belgici, he proposed several possible names for the innermost of the large moons of Jupiter, including The Mercury of Jupiter or The First of the "Jovian Planets". Based on a suggestion from Johannes Kepler in October 1613, he also generated a naming scheme so that each moon was given its own name based on the lovers of the Greek mythological Zeus or his Roman equivalent, Jupiter. In this case, he named the innermost large moon of Jupiter after the Greek mythological figure Io. Marius' names were not widely adopted until centuries later, and in much of the earlier astronomical literature, Io was generally referred to by its Roman numeral designation (a system introduced by Galileo) as "Jupiter I", or as "the first satellite of Jupiter".

Features on Io are named after characters and places from the Io myth, as well as deities of fire, volcanoes, the Sun, and thunder from various myths, and characters and places from Dante's Inferno, names appropriate to the volcanic nature of the surface. Since the surface was first seen up close by Voyager 1 the International Astronomical Union has approved 225 names for Io's volcanoes, mountains, plateaus, and large albedo features. The approved feature categories used for Io for different types of volcanic features include patera (volcanic depression), fluctus (lava flow), vallis (lava channel), and active eruptive center (location where plume activity was the first sign of volcanic activity at a particular volcano). Named mountains, plateaus, layered terrain, and shield volcanoes use the terms mons, mensa, planum, tholus, respectively. Named, bright albedo regions use the term regio. Examples of named features include Prometheus, Pan Mensa, Tvashtar Paterae, and Tsũi Goab Fluctus.