Ket-Cheleb (also known as Vulcan/Vulcanis A I, Nevasa I, Ko'vel I or 40 Eridani A I) was a planet, the first planet in the 40 Eridani star system, in orbit of the star 40 Eridani A. (Last Unicorn RPG modules: The Way of Kolinahr, Planets of the UFP)
- The first planet of Vulcan's system was first mentioned as early as ST reference: Spaceflight Chronology, although it was never named except in two installments of the Last Unicorn RPG. ST reference: Star Trek Maps identified the system's first world as Vulcan itself, omitting all references to additional planets beside Vulcan's sister world.
Ket-Cheleb was located close to the central star, too close in fact to support any semblance of a lifeform-supporting planetary atmosphere. Unlike other bodies in the system, Vulcan I's orbit was at a slight angle to the orbital plane. (ST reference: Star Charts)
- While Star Charts identified this as a class B geomorteus planet, the Last Unicorn RPG supplements that name the world both called it a class F planet
Vulcan I also appears in the reference book The Worlds of the Federation, however no details are given other than it being the first planet in the system. Both The Worlds of the Federation and Star Charts show it to be the smallest planet in the system, although it appears to be slightly smaller in Star Charts.