According to the episode's script, the pronunciation was "Oar-LEE-us 9". . However, according to Startrek.com, the pronunciation for Orelious was "oh-REE-lee-us". 
According to the Star Trek: Star Charts (pgs. 36, 47), the Orelious system was located in non-aligned space. This system, also known as Orellius, was a single star system. Orelious was a F class star with a magnitude of +5, which was the same brightness as Sol.