Los puntos clave no están disponibles para este artículo en este momento.
This is a preliminary report on surface photometry of the major fraction of known globular clusters, to see which of them show the signs of a collapsed core. We find more than 20 examples, or one-fifth of the total. Core classifications are given for all clusters examined. The fraction of collapsed-core clusters may be an index of how long a cluster takes to reexpand after collapse.
Djorgovski et al. (Sun,) studied this question.