Stellar engine

Diagram of a class-C stellar engine (to scale) built around a Sun-like star. It consists of a partial Dyson swarm composed of 5 Dyson rings of solar collectors (the class-B component), and a large statite Shkadov thruster (the class-A component). Perspective is from below the system's ecliptic at a distance of ~2.8 AU. The system's direction of acceleration is on a vector from the center of the star through the center of the Shkadov thruster, which is hovering over the star's north pole (with regards to the ecliptic), at a distance of 1 AU.

Stellar engines are a class of hypothetical megastructures which use the resources of a star to generate available work (also called exergy). For instance, they can use the energy of the star to produce mechanical, electrical or chemical work, or they can use the impulse of the light emitted by the star to produce thrust, thus controlling the motion of the star system. The variants which produce thrust may accelerate a star and anything orbiting it in a given direction. The creation of such a system would make its builders a Type II civilization on the Kardashev scale.

Proposed applications for stellar engines include moving a star system to avoid astrophysical hazards, such as the supernova of a neighboring star, or to come into close proximity to another system in order to colonize it.