Helior

Helior is a fictional celestial body that appears in science fiction and speculative fiction as the primary planet of the Helior system. In most depictions, Helior is a terrestrial world with oceans and continents, orbiting a main-sequence star and accessible to human or humanoid civilizations through space travel. The exact size, atmosphere, and climate vary by author, but common elements include a rocky surface, a moderate to dense atmosphere, and liquid water at or near the surface. Some works assign a magnetic field and plate tectonics, while others imagine extreme greenhouse conditions or arid outcrops.

The name Helior is usually linked to the idea of sun or light, drawing on roots related to Helios, though spellings differ across languages and franchises. In many settings, Helior serves as a frontier world, a research outpost, or the political center of a planetary federation.

As a fictional setting, Helior has been used to explore themes such as colonization, ecological balance, and the long-term survivability of sentient life in a changing climate. The planet's biosphere, if depicted, ranges from microbial-dominated landscapes to complex ecosystems with endemic life forms adapted to its day-night cycle and atmospheric composition.

See also: Exoplanet in fiction, Planetary science in popular culture, Terraforming in fiction.