Sustainable circular orbits near gravitating scalar configurations

In this work necessary conditions for the existence of an event horizon and circular orbits in the vicinity of the horizon for static spherically symmetric gravitating scalar configurations is obtained. It is shown that the radii of the horizon and photon orbit for a scalar black hole are always less than corresponding values for the vacuum black hole with the same mass. Exact mathematical models of scalar black holes, for which radii of the horizon, photon orbit and innermost stable circular orbit tend to zero as the scalar field intensity increases at a fixed mass, are constructed. The identification problem for gravitating scalar configurations by means of observation parameters of orbits near inner edges of their accretion disks is discussed.