Dyson ring
Dyson rings constructed by Species 10-C
A Dyson ring was a type of megastructure that encircled a star.
In 2381, the USS Cerritos visited the Dyson ring world of Corazonia to repair the sentient environmental control computer of Vexilon. (LD: "In the Cradle of Vexilon")
In 3190, the USS Discovery discovered a set of Dyson rings around an extragalactic star believed to have been constructed by Species 10-C, as they were composed of a silicon-ellanium alloy, the same rare material as the DMA controller. (DIS: "Rosetta")
Another set of Dyson rings were present around Species 10-C's new home star inside the hyperfield. (DIS: "Coming Home")
In one of the many alternate universes visited by the USS Beagle, a Human civilization had built Dyson rings around Sol. (LD: "Fissure Quest")