Kyr was a star, spectral class G5, that was at the center of the star system containing the planet Kyros. It was described as calm and unremarkable when put to the spectrograph by Montgomery Scott when the USS Enterprise visited the system in the 2260s. The Kyr system was occasionally bathed in radiation propelled through subspace by the nearby binary black holes at Epsilon Ionis. (TOS novel: Spock, Messiah!)