To the Globular Cluster Classification Problem. Calculating the Concentration of Stars for 26 Clusters

In view of the absence of a satisfactory solution to the globular cluster (GC) classification problem, we have searched for a physical parameter that admits of the GC classification and finding empirical dependences on observed physical characteristics. For this purpose, we have considered a model of the apparent density in GCs with three free parameters. Using the widely known simplex method of minimizing the square of the difference between the observed and theoretical densities, we have found the corresponding free parameters for 26 GCs. As observational data we have taken mostly the density profiles constructed by Miocchi et al. (2013) based on a combination of Hubble Space Telescope and ground-based data. One of the free parameters of our model characterizes the concentration of stars toward the GC center. We have found a number of empirical dependences of this parameter on the main physical characteristics of GCs. The derived empirical formulas can be used in determining these characteristics for other GCs via the concentration and vice versa.

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