A concussion ring was a phenomenon associated with supernovas, like the Phi Puma supernova.
By 2165, the concussion ring of that supernova was approximately ninety light years in diameter. In 2165, Bayard's Planet was at the rim of this concussion ring. (TNG: "The Naked Now", production art)
This was seen on an Enterprise computer's star chart, originally a drawing by Rick Sternbach and published, years earlier, on page 151 of the reference titled "Spaceflight Chronology".