The Hanoli system was a remote and uninhabited star system.
In the mid 23rd century, a Vulcan science vessel discovered a subspace rupture in the Hanoli system. The Vulcans attempted to seal the rupture with a pulse wave torpedo, but instead caused the rupture to expand exponentially. The entire star system, including the Vulcans, was wiped out. (DS9: "If Wishes Were Horses")
The 23rd century date is contradicted by another line in the episode, which placed this incident in the 22nd century.