From Bravo Fleet Infobase
Near the Solaria Nebula
Unmanned Starfleet Probe
The Ariel Nebula is a small nebula in The Round Table, located within a few light-years of the Solaria Nebula. Due to its close proximity, the Ariel is considered a "child nebula" of the Solaria, even though it appears to have formed independently. It is the site of Research Station Ariel, one of the first Federation outposts in the Round Table, which was constructed to study the nebula's properties in mid-2384. The nebula is considered safe for travel and long-term habitation.
In 2384, the undefended Research Station Ariel, which was working on temporal rift technology at the time, was assaulted and captured by a group of unidentified mercenaries. These mercenaries (incredibly) finished the research, built a prototype, and opened a temporal rift to pull a sapient extra-dimensional lifeform into our continuum. They attempted to control the creature, which communicated telepathically, but they were largely unsuccessful. As the nebula filled with the deadly radiation that constituted the energy being's manifestation in our reality, the nebula became extremely unsafe for travel.
Fortunately, the crew of the U.S.S. Xelisa was able to recapture the station (along with a mercenary defector) and send the creature back to its own continuum (Captain. Research aboard the station has resumed, and a number of very interesting academic papers have been written by the scientists stationed there in the months since the attack. Other than that, by all accounts, life in the Ariel Nebula has been quite boring ever since.