Paraagan II was a planet visited in early 2152 by the Enterprise NX-01. The planet had a Paraagan mining colony. When the colony started in 2132 there were thirty miners; by 2152 there were 3,600 colonists, plus schools, landscaped communities, and a museum. The colonists were somewhat nonconformist by Paraagan standards, eschewing most of the ceremonies of mainstream society.
The atmosphere of the colony planet contained a large amount of tetrazine that reacted poorly with plasma. When the Enterprise shuttlepod approached the planet, the atmosphere was ignited and all the Paraagan colonists were killed. It was later determined that the cause was a device planted by a Suliban stealth-cruiser that caused the released plasma. The Suliban Cabal were believed to have caused the destruction of Paraagan II to stop the mission of the Enterprise by besmirching its name, thereby gaining an advantage in the Temporal Cold War. (ENT: "Shockwave")
The novel Watching the Clock explains that the Cabal's primary motives in destroying Paraagan II- or the motives of their benefactor, at least- were to eliminate the ancestors of a scientist who would attend a vital conference with other specialists in temporal physics in 2381. However, this part of the plan was unsuccessful as Daniels was able to arrange for the scientist's ancestors to win an off-world cruise just before the destruction occurred, ensuring that he would survive to the time of the conference.