Using the Hellings-Nordtvedt theory, some expressions are obtained of the mass defect effect for a type of charged celestial body in a gravitational field with a nonzero cosmological constant λ. And the mass defects are obtained in several other types of fields and under different conditions by discussing the parameters in the expressions. These are meaningful calculations of the radiated energies in the processes of forming those kinds of celestial bodies in astrophysics.