Susreu

Susreu is a fictional exoplanet commonly referenced in speculative fiction and worldbuilding. In many depictions it orbits a dim red dwarf near the inner edge of the habitable zone, producing marked day-night contrasts. The name is often tied to an ancient in-universe language and has become a standard example in discussions of planetary habitability.

Physically, Susreu is described as a rocky world with a radius about 1.3 times that of Earth and a mass around two to three Earth masses. Its atmosphere is usually CO2-rich with trace nitrogen, yielding surface pressures near 0.6 bar. Liquid water is rare on the surface and tends to occur in highland basins or subsurface reservoirs. The climate is characterized by strong seasonal swings driven by orbital eccentricity and by intense stellar irradiation from the red dwarf.

Geologically, the surface features basaltic plains, fault zones, and signs of past geothermal activity. Several treatments imagine a subsurface ocean beneath an ice crust, which would offer potential habitats for life in a fictional setting.

Exploration and cultural significance: In worldbuilding contexts, Susreu is used to illustrate challenges of exploration, resource management, and habitability in low-pressure, cold environments. It provides a backdrop for stories about scientific discovery and colonization under harsh stellar conditions.

See also: Exoplanet, Habitability, Worldbuilding.