A high-precision two-dimensional stellar evolution code has been developed for studying solar variability due to structural changes produced by varying internal magnetic fields of arbitrary configurations. Specifically, we are interested in modeling the effects of a dynamo-type field on the detailed internal structure and on the global parameters of the Sun. The high precision is required both ...

Properties, structure, and thermal evolution of neutron stars are determined by the equation of state of stellar matter. Recent data on isospin-diffusion and isoscaling in heavy-ion collisions at intermediate energies as well as the size of neutron skin in Pb have constrained considerably the density dependence of the nuclear symmetry energy and, in turn, the equation of state of neutron-rich n...

This paper gives an overview of the properties of all possible equilibrium sequences of compact strange-matter stars with nuclear crusts, which range from strange stars to strange dwarfs. In contrast to their non-strange counterparts, –neutron stars and white dwarfs–, their properties are determined by two (rather than one) parameters, the central star density and the density at the base of the...

We investigate stationary axisymmetric configurations of magnetized stars in the framework of general relativistic ideal magnetohydrodynamics. Our relativistic stellar model incorporates a toroidal magnetic field and meridional flow in addition to a poloidal magnetic field for the first time. The magnetic field and meridional flow are treated as perturbations, but no other approximation is made...

We investigate the motion, near the equilibrium configurations, of an initially spinless rigid body subject to an external tidal field. Two cases are considered: when the center of mass of the body is at rest at the equilibrium point of the field generated by a generic mass distribution, and when it is placed on a circular orbit subject to a spherically symmetric potential. A complete analysis ...

We developed a Monte-Carlo code for the treatment of the radiative transfer in arbitrary clumpy dust configurations. Both the radiation of the (central) energy source(s) and the thermal emission of the dust are considered. Intensity and polarization maps of the modelled objects can be computed. As the first application of our code we studied the radiative transfer in a spherical two-phase clump...

Using the two-fluid formalism with the polytropic approximation, we examine the axisymmetric stability criterion for a composite system of gravitationally coupled stellar and gaseous singular isothermal discs (SIDs). Both SIDs are taken to be infinitely thin and are in a self-consistent steady background rotational equilibrium with power-law surface mass densities (∝ r) and flat rotation curves...

We study collective wind configurations produced by a number of massive stars, and obtain densities and expansion velocities of the stellar wind gas that is to be target, in this model, of hadronic interactions. We study the expected γ-ray emission from these regions, considering in an approximate way the effect of cosmic ray modulation. We compute secondary particle production (electrons from ...

We consider propagation of waves in a stratified non-isothermal magnetic atmosphere. The situation of interest corresponds to waves in the outer solar (chromosphere and corona) and other stellar atmospheres. The waves are simulated by using a high-resolution, well-balanced finite volume based massively parallel code termed SURYA. Numerical experiments in both two and three space dimensions invo...