UNIFORM NEWTONIAN MODELS WITH VARIABLE MASS

A Newtonian version of the spatially homogeneous and isotropic cosmological models with variable mass is presented. Under the assumption that the mass variation is a strict cosmological effect, its influence on the evolution of the scale function is established for the case of a dustfilled universe. Unlike the usual Newtonian models the present value of the deceleration parameter (q congruent-to 1) obtained from the luminosity distance versus redshift relation can be fitted for a time-decreasing mass. It is also shown that the hyperbolic, parabolic or elliptic character of the fluid motion can be modified along the expansion. Likewise, a Friedmann-type equation with a variable "curvature term" indicates that in the framework of a full geometric variable mass theory, the same may occur with the open, flat or closed character of the universe spatial section.