Stirnis is a neutron star with an associated system, on the edge of Federation space, somewhere in the galaxy's Alpha or Beta Quadrants.
History and specifics[]
The planets Sierra-Bravo 112 and Sierra-Bravo 112-II are located in the vicinity of the Stirnis system.
In the year 2373, rogue Cardassians, working with the Drek'la, invaded the system that orbits Stirnis. (DS9 - Rebels novel: The Conquered)