The M15 is a globular cluster in the constellation Pegasus. It is estimated to be 13.2 billion years old, one of the oldest globular clusters. M15 is at a distance of about 33,600 light-years from Earth. It has an absolute magnitude of -9.2 which translates to a total luminosity of 360,000 times that of the Sun. Messier 15 is one of the most densely packed globulars known in the Milky Way galaxy. The core of this cluster has undergone a contraction known as core collapse and it has a central density cusp, with an enormous number of stars surrounding what may be a central black hole.
