Naiad orbits a class M red dwarf at 6.28 million kilometers (0.042 AU). It is tidally locked to its star Poseidon, and orbits in 10.1 Earth days (1 local day). Poseidon appears as a bright red disc in the sky about 1.5 times the angular diameter of a full moon. The light it casts is correspondingly dim, just bright enough to read by.
Because Naiad is tidally locked with Poseidon, the planet is covered by continual gale-force winds and strong ocean currents that travel from the area directly “beneath” the sun to the far side of the planets, where coriolis forces twist the winds into a continent-sized hurricane and water vortex.
Naiad’s surface is not immediately lethal, but not inhabitable. Between periodic stellar mass ejections and the continual winds and solar radiation, anything not capable of living permanently below several meters of water cannot survive. Thus, Naiad is an utterly barren world on and above its surface.
Naiad’s people live in roving submarine flotillas, usually focused around one or more food processing ships. The submarines are usually run by extended family units, with each sub staying in the fleet and being repaired and rebuilt over generations. These subs mostly handle fishing and food capture, and security for those fishing and capturing foods. Others act as hospitals, warehouses, and drydocks.
Naiad’s people are fiercely independent, loyal only to family and tribe. Due to their isolation, they’re largely ignorant of the rest of the clusters, aware but unconcerned that offworlders send ships to pick up all the seafood they harvest. News travels slowly among the Naiadeen.
The Naiadeen have atomic technology, and most of their subs run on nuclear fission reactors. Naiad is rich in heavy elements, and some tribes make a lucrative living collecting fissionables from undersea mines. Their technology is simple and reliable, often benefiting from high-tech manufacturing and a stiff dose of General Products parts and tools (one of Naiad’s few imports).
Thanks to their underwater environment and dangerous animals like the Naiadeen Giant Mantis Shrimp, life on Naiad is tough and not for outsiders. General ignorance of life on Naiad, coupled with their perceived simple-mindedness, makes the Naiadeen the butt of “redneck” jokes throughout the cluster.