We investigate the evolution of low-mass metal-free Population III stars. Emphasis is laid upon the question of internal and external sources for CNO-elements, which – if present in sufficient amounts in the hydrogen-burning regions – lead to a strong modification of the stars’ evolutionary behavior. For the production of carbon due to nuclear processes inside the stars, we use an extended nucl...

We present a hyperbolic formulation of the evolution equations describing non-radial perturbations of slowly rotating relativistic stars in the Regge–Wheeler gauge. We demonstrate the stability preperties of the new evolution set of equations and compute the polar w-modes for slowly rotating stars.

A short introduction is given to astrophysics of neutron stars and to physics of dense matter in neutron stars. Observed properties of astrophysical objects containing neutron stars are discussed. Current scenarios regarding formation and evolution of neutron stars in those objects are presented. Physical principles governing the internal structure of neutron stars are considered with special e...

Using the standard infall model of Galactic chemical evolution, we explore the origin of carbon and calculate the abundance evolution of CNO elements for 8 different models of stellar nucleosynthesis yields. The results show that, in the early stage of the Galaxy, massive stars are the main producer of carbon, and that as our Galaxy evolves to the late stage, the longer lived intermediate-and l...

The cooling of compact isolated objects for different values of the gravitational mass has been simulated for two alternative assumptions. One is that the interior of the star is purely hadronic[1] and second that the star can have a rather large quark core [2]. It has been shown that within a nonlocal chiral quark model the critical density for a phase transition to color superconducting quark...

We study the stellar population history and chemical evolution of the Milky Way in a hierarchical ΛCDM model for structure formation. Using a Monte Carlo method based on the semi-analytical extended Press & Schechter formalism, we develop a new code GAMETE (GAlaxy MErger Tree & Evolution) to reconstruct the merger tree of the Galaxy and follow the evolution of gas and stars along the hierarchic...

In order to put strict observational constraints on the evolutionary status of the magnetic chemically peculiar stars (CP2) of the upper main sequence, we have investigated a well established sample of galactic field CP2 objects within a radius of 200 pc from the Sun in the (X,Y) plane. In total, 182 stars with accurate parallax measurements from the Hipparcos satellite were divided into Si, Si...

Context. Very massive stars pass through the Wolf-Rayet (WR) stage before they finally explode. Details of their evolution have not yet been safely established, and their physics are not well understood. Their spectral analysis requires adequate model atmospheres, which have been developed step by step during the past decades and account in their recent version for line blanketing by the millio...

While the basic properties of AGB stellar evolution are well established, comprehensive observational studies of late phases of intermediate mass stars continue to generate puzzles for current stellar models. Here, I review current techniques to model AGB stars, and I discuss important aspects of current research of AGB (and post-AGB) stellar evolution with a particular focus on how these inter...

Abstract. In this paper we briefly review our recent results on evolution and properties of isolated neutron stars (INSs) in the Galaxy. As the first step we discuss stochastic period evolution of INSs. We briefly discuss how an INS’s spin period evolves under influence of interaction with turbulized interstellar medium. To investigate statistical properties of the INS population we calculate a...