M15 are shown in this Hubble Space Telescope (HST) image taken in April of 1994. The stars revealed are contained in an area 1.6 light years across and their colors roughly indicate their temperatures - hot stars appear blue, cooler stars look reddish-orange. M15 has long been recognized as one of the densest cluster of stars in our galaxy outside of the galactic center itself. Even the unprecedented resolving power of the HST cameras could not separate the individual stars in its innermost regions. However, this HST image reveals that the density of stars continues to rise toward the cluster's core, suggesting that a sudden, runaway collapse due to the gravitational attraction of many closely packed stars or a single central massive object, perhaps a black hole, could account for the core's extreme density.
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Publications with keywords: M 15
Publications with words: M 15