Any world with an eccentricity greater than 0.35 is classified as an Ikarian type world, from the name of an ancient (Old Earth) mythological figure, Ikaros, who ventured too close to the Sun. This classification is supplementary to other NOLWOCs classification classes and types, so that an eccentric gas giant is classed as an Ikarian Jovian, and eccentric Earth-like worlds are known as Ikarian Gaian worlds, and so on.
Ikarian Gaian worlds are notable for the fact that the main factor governing their seasons is not the tilt (obliquity) of the world, but rather the eccentricity. When an Ikarian terrestrial world is near its star at periastron it will receive much more heat and light than when at its furthest point (at apastron). Such planets move more quickly in their orbit at periastron, and therefore a Ikarian world's summer is short, while the winter season is considerably longer.
Ikarian worlds of all types are very common, and nearly a third of all gas giants are highly eccentric. However such eccentric giants tend to scatter other planets out of their system at an early stage, so planetary systems with Ikarian giant worlds tend to hold fewer terrestrial class worlds.
Examples of colonised Ikarian worlds include Perdix, Diwali (a moon of an eccentric jovian).