Hydrodynamic Calculations of Spherical Gravitational Collapse in the Scalar-Tensor Theory of Gravity

Abstract

Hydrodynamic equations for spherical gravitational collapse in the scalar-tensor theory of gravity are approximated by finite-difference equations. The dynamical motion of a gaseous sphere is calculated numerically on the assumption that the sphere consists of a perfect gas without energy flow and, therefore, its total mass is conserved. In order to avoid the difficulty of ~atching of the metric and scalar fields at .the surface of the gaseous sphere, the sphere is divided into two parts, i.e., a central core and an extended tenuous atmosphere. In the collapsing core, scalar waves are generated around its central region at the final stage, but their effect is not so large as to deviate various physical quantitiEs appreciably from those to be obtained in the general relativistic treatment, except in the inner-most region of self-closure.