Artificial sunlight generation systems girdling jovian worlds brown dwarfs, or other dimly luminous stars. Also known as equatorial sunlines.
There are three classes of sunline;
- Class 1 sunlines, a form of gas giant stellification technology, use self-replicating fusion or conversion reactor units in the atmosphere of a gas giant or brown dwarf to produce a luminous equatorial band, which will illuminate the planet or dwarf's moons and worldlets with visible light. These moons and worldlets can then be be terraformed in a variety of ways.
- Class 2 sunlines, known as stellar sunlines, orbit various kinds of star, and collect emitted light from the star's surface and concentrate it into focused beams which can illuminate distant planets in the outer planetary system. This allows even cold outer system objects to be terraformed. The stellar sunline generally orbits in the plane of the equator, and sends collimated beams of light towards the various illuminated objects. Because the light is concentrated on specific objects the system is very efficient, and from most angles the sunline is difficult to see.
- Class 3 sunlines: A Class 3 sunline is a hybrid system that incorporates features of both Class 1 and Class 2 sunline design. Class 3 sunlines orbit various types of gas giant and brown dwarf and use a system of skyhooks and orbital rings or mass streams to extract material from the central body and deliver it to the sunline array. The material is then burned using high efficiency fusion or conversion reactors within the sunline and the resulting energy used to illuminate the moons and habitats in orbit. Depending on the design, the entire equatorial orbit of the central body may be illuminated or focused beams may be sent to specific orbital locations with the bulk of the system limited to only natural illumination.