Dikon Alpha was a Class 9 pulsar.
In 2370, when choosing a site that could produce vertion particles if a modified photon torpedo detonated inside it, the crew of the USS Enterprise-D had to choose between two candidates. The candidates were Dikon Alpha and the MacPherson Nebula. Based on the recommendation of Chief Engineer Geordi LaForge, the Enterprise set a course for the nebula. (TNG: "Emergence")