Cheron (Omicron Gruis). Primary was a Class F star. It had a magnitude of -1, which was 100 times brighter than Sol. This system was located in the Romulan War Theater of Operations (2156-60), and was the site of a battle. This was the Cheron where an allied fleet fought the Romulans and won. (Pages 60 & 66-67)
An article in the Picard family album, which may not have been seen on-screen, titled "Foe in retreat after Cheron debacle", apparently in reference to this battle. Unfortunatly, the rest of the article content is unknown.