Journal of Physical Studies 22(1), Article 1901 [12 pages] (2018)


M. V. Vavrukh, D. V. Dzikovskyi, S. V. Smerechynskyi

Ivan Franko National University of Lviv, Department for Astrophysics,
8, Kyrylo and Methodiy St., Lviv, UA--79005, Ukraine

The energy of the ground state of a spatially homogeneous electron-nuclear model has been calculated in the reference system approach at high densities. The equation of state has been constructed in the approximation of the two-particle correlations of the relativistic degenerate homogeneous electrons model at the absolute zero temperature on a background of a positive compensating charge, which is necessary for the description of the white dwarf's inner structure. The relative decrease of pressure has been investigated as a function of the nuclear charge and a relativistic parameter. The equilibrium equation without rotation has been solved at the first stage. Here we have investigated the influence of interparticle interactions on the characteristics of a spherically symmetrical model. By using rescaling, the exact equilibrium equation for the model with axial rotation and interparticle interactions has been reduced to an equilibrium equation in partial derivatives for the model which takes into account the rotation with constant angular velocity, but without interparticle interactions. The approximate solutions to the obtained equation have been found numerically. Within this approach we have calculated the mass, the polar and equatorial radii as functions of the relativistic parameter in the stellar centre and dimensionless angular velocity. The dependence of the maximal angular velocity and maximal dwarf's mass on the relativistic parameter has been analyzed, as well as the resulting effect of interparticle interactions and axial rotation, which are competing factors, on the characteristics of massive dwarfs. It has been shown that the axial rotation causes an increase in the mass and size of a dwarf, while the interactions cause their decrease; moreover the influence of interparticle interactions essentially depends on the chemical composition. Also, we have established the conditions under which the axial rotation can compensate for weight loss of mass due to the Coulomb interactions. In addition, we have provided the tables of the characteristics' variations as the functions of the model parameters.

PACS number(s): 97.20.Rp, 97.60.Bw, 04.40.Dg