The MacPherson Nebula is a supernova remnant, located less than twelve hours from the Cordannas system at warp 9.

In 2370, the USS Enterprise-D identified the MacPherson Nebula as an alternate source of vertion particles to sustain a network of semi-intelligent emergent circuit nodes on board, which was in the process of creating a new emergent lifeform. The Enterprise detonated a modified photon torpedo in the interior of the nebula, producing enough vertion particles for the nodes to complete their function. (TNG: "Emergence")