Carcosans

Carcosa is Alpha Sagittarii III, a class-M planet whose sun is a blue main sequence A-class dwarf star located in the Beta Quadrant about 181 light-years from Earth. Travel time from Earth to Carcosa is six months at Warp 6. The closest Federation-settled planet to it is Belle Terre.

It shares the name of a fictional city in both the book, The King in Yellow, and in the Darkover series of novels. It was settled in the 2270s, at about the same time as the Belle Terre system, by colonists who wanted to settle a world far away from Federation interference. It was so named by a colonist looking out at a misty lake on a foggy night, who saw long-abandoned ruins on the other side of the lake.

Because of time dilation, considerable time has passed on Carcosa since the original colony ship arrived over a century ago. This has given the colonists' descendants time to form their own unique culture, and genetic drift has caused some traits, such as paranormal abilities, to appear in some of the population.