The Hayashi system was an uninhabited planetary system.

In 2366, the USS Enterprise-D was preparing detailed exospheric charts of the system as a prelude to colonization. Its mission was interrupted by the USS Hood, concerning a recent discovery at Beta Stromgren. (TNG: "Tin Man")

Hayashi system appeared in the starchart Data and Picard were studying in Stellar Cartography in 2371. (Star Trek Generations, display graphic)