Beta Magellan
From Memory Alpha, the free Star Trek reference
Beta Magellan is the central star of the Beta Magellan system. A star in that system went supernova in 2364. The supernova occurred earlier than the nearby Bynars anticipated, and the resulting electromagnetic effects disabled their planetary computer on Bynaus. (TNG: "11001001")
It is not stated in the episode that the central star is the one that went supernova, only that a "star in the system" went supernova.
