Betelgeuse III

Betelgeuse III was a planet in the Betelgeuse star system. It was not class M, as it had an ionized atmosphere.

History
In 2366, while investigating the death of Lynn Costa in a laboratory, Worf and others checked eight environmental pods which emulated climates on other planets. One of them had a display screen specifying that it was a simulation of Betelguese III, describing it with the notation "ionized atmosphere, udryxal compound process refinement, and space vacuum". One of the other pods had malfunctioned, allowing deadly gases to escape and kill Costa.