Kyr was a star, spectral class G5, with an associated star system, located somewhere in the space of the galaxy's Alpha or Beta Quadrants.
History and specifics
The Kyr system's orbit was the location of a planetary system, including the world Kyros. It was described as calm and unremarkable when put to the spectrograph by Montgomery Scott when the Federation starship USS Enterprise visited the system in the 2260s decade. The Kyr system was occasionally bathed in radiation propelled through subspace by the nearby binary black holes at Epsilon Ionis. (TOS novel: Spock, Messiah!)