We present a detonating failed deflagration model of Type Ia supernovae. In this model, the thermonuclear explosion of a massive white dwarf follows an off-center deflagration. We conduct a survey of asymmetric ignition configurations initiated at various distances from the stellar center. In all cases studied, we find that only a small amount of stellar fuel is consumed during deflagration pha...

Using Zeeman observations of the H30α recombi-nation line maser transition at 1.3 mm we have detected a magnetic field which is associated with the corona of the circum-stellar disk of MWC 349. At a radial distance of 40 a.u., where the H30α maser is located, the line–of–sight component of the field is approximately parallel to the plane of this edge–on disk, and its average strength is 22 mG. ...

Aims. To calculate transition rates from ground and excited states in neutral oxygen atoms due to electron collisions for non-LTE modelling of oxygen in late-type stellar atmospheres, thus enabling reliable interpretation of oxygen lines in stellar spectra. Methods. A 38-state R-matrix calculation in LS -coupling has been performed. Basis orbitals from the literature (Thomas et al.) are adopted...

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 ...

We investigate spherically symmetric, static matter configurations with polytropic equation of state for a class of fðRÞmodels in Palatini formalism and show that the surface singularities recently reported in the literature are not physical in the case of Planck scale modified Lagrangians. In such cases, they are just an artifact of the idealized equation of state used. In fact, we show that f...

In optical aperture-synthesis imaging of stellar objects, different beam combination strategies are used and proposed. Coaxial Michelson interferometers are very common and a homothetic multiaxial interferometer is recently realized in the Large Binocular Telescope. Laboratory experiments have demonstrated the working principles of two new approaches: densified pupil imaging and wide field-of-v...

Having constructed the equilibrium stellar configurations, we are now poised to ask whether they are stable to small perturbations. This leads us to the subject of relativistic stellar pulsations. One may classify such pulsations by their angular dependence: when we investigate the full subject we will find modes of every spherical harmonic index l ≥ 0. However, for the cold stars of interest t...

Some features of hydroand thermodynamics, as applied to atmospheres and to stellar structures, are puzzling: 1. The suggestion, first made by Laplace, that our atmosphere has an adiabatic temperature distribution, is confirmed for the lower layers, but the reason why it should be so is difficult to understand. 2. The standard treatment of relativistic thermodynamics does not allow for a systema...