A peak of radiation from the planet Dathyna's massive, metal-rich, irregularly variable sun, which probably condensed near a recent supernova, destroyed civilization but produced a killer mutation which exterminated the parent race, appropriated its technology and now threatens the Polesotechnic League.
-copied from here.
Sun middle-F type, 5.4 times as luminous as Sol, more white than gold;
less hydrosphere than Earth because solar ultraviolet splits water molecules;
lower mountains and continents;
shallow, tideless, algae-covered ocean over half the flatter surface;
slight axial tilt;
small edge effects;
poles similar to the equator;
steep air pressure gradient;
uplands of ice and rock;
large deserts with dust storms over red rock;
fertile areas with forests, meadows and crops;
the dominant species inhabiting large, partly ruined buildings.