L-374
From Memory Alpha, the free Star Trek reference.
The L-374 system is a star system near the L-370 system. The system was attacked by the Doomsday machine in 2267. It had four rocky planets that were observed prior to the attack; the two outer planets were consumed as fuel by the machine before it could be destroyed by the starships USS Enterprise and USS Constellation. (TOS: "The Doomsday Machine")
