Perennons

Perennons is a fictional celestial body featured in the science fiction novel "Starfall." It is depicted as a rogue planet, meaning it does not orbit a star. Instead, Perennons drifts through interstellar space, a cold and dark world. Its environment is characterized by extreme temperatures and a lack of natural light, with any illumination originating from its own internal geothermal activity or occasional passing nebulae.

The inhabitants of Perennons, the Xylos, are a sentient species adapted to this harsh existence. They are described as bioluminescent, capable of generating their own light for communication and navigation. Their society is largely subterranean, utilizing vast cave systems and geothermal vents for survival and shelter. The Xylos have developed advanced technologies focused on energy manipulation and terraforming within their limited confines, a necessity for sustaining life on their starless world. Perennons serves as a central location for much of the novel's narrative, highlighting themes of isolation, adaptation, and the search for a new home among the stars as the Xylos face an existential threat to their home planet.