Rolor Nebula

From Memory Alpha, the free Star Trek reference

The Rolor Nebula is an interstellar dust cloud located near the Demilitarized Zone, in the flight path between the Bajoran system and the Dreon system. Ships moving between the two systems generally go around the nebula. In 2372, Captain Benjamin Sisko questioned Kasidy Yates on which alternate route she took to avoid the Rolor Nebula, when he was suspicious of her possible involvement with the Maquis. (DS9: "For the Cause")