The Hadyn Nebula, commonly known as Gamma's Bermuda Triangle, is located between the Valara System and the Kendi System in the Gamma Quadrant.
In 2372, the USS Cochrane became the first Federation starship to encounter the nebula. The Cochrane was unable to study the nebula beyond a high-fidelity scan and left several Class Two probes behind to collect more data. When the USS Karnack arrived several weeks later, none of the probes were to be found. It did detect unusual gravimetric readings at the heart of the nebula. Unfortunately, a passing Dominion patrol forced the Karnack to flee. Other than a few stolen opportunities for scans, Starfleet knows very little about the nebula.