The 13 October1967 review of the script by de Forest Research panned the name M24 Alpha, stating: "Antiquated astronomical nomenclature used letter M to mean magnetic cloud. Such "clouds" have since been proven to be extra-galactic star clusters. And Star Trek Guide says series is not to journey outside our galaxy. A star system would be designated by Greek letter and constellation name (Mu Andro-medae), or by New General Catalogue (NGC) number, or by star name, real or imaginary.
According to Star Trek Maps (p. 27), Triskelion was the second planet in the system.