Praesitlyn V is a highly toxic world in the Praesitlyn system of the Sluis sector. Beneath the poisonous atmosphere is a rocky planet, but sensor probes have revealed that the planet is littered with hazardous features, and even if the atmosphere could be cleaned, it is doubtful a colony could prosper.
Many experts believe that the current problems were caused by a highly advanced species, as of yet undiscovered, who were testing extremely powerful weapons. There is even evidence of anti-matter annihilation tests, which could have caused an ecological disaster of this sort. There are no known historical events that have transpired here, only the aforementioned evidence of alien activity.