The Hekaras sector was a sector of space almost completely filled by tetryons. The only area free of tetryons and the only safe route through the sector was the Hekaras Corridor. The planet Hekaras II was also located in this sector.
In 2370, it was discovered that the use of warp fields had seriously damaged the barrier between subspace and normal space in the Hekaras sector. If warp travel were continued with no limits, the sector would be filled with subspace rifts by 2410. (TNG: "Force of Nature")