Related papers: Light curve variation caused by accretion column s…
Disk accretion to rotating stars with complex magnetic fields is investigated using full three-dimensional magnetohydrodynamic (MHD) simulations. The studied magnetic configurations include superpositions of misaligned dipole and quadrupole…
The physics of the "hot spots" on stellar surfaces and the associated variability of accreting magnetized rotating stars is investigated for the first time using fully three-dimensional magnetohydrodynamic simulations. The magnetic moment…
The paper presents the results of three-dimensional (3D) modelling of the structure and the emission of accretion columns formed above the surface of accreting strongly magnetized neutron stars under the circumstances when a pressure of the…
We present radiation transfer models of rotating young stellar objects (YSOs) with hotspots in their atmospheres, inner disk warps and other 3-D effects in the nearby circumstellar environment. Our models are based on the geometry expected…
Global 3-D magnetohydrodynamical simulations have been conducted to study magnetospheric accretion around stars with various spin rates. For slow rotators, characterized by a fastness parameter $\omega_s\lesssim 0.78$, the disk's inner edge…
The discovery of high-amplitude brightness oscillations during type I X-ray bursts from six low-mass X-ray binaries has provided a powerful new tool to study the properties of matter at supranuclear densities, the effects of strong gravity,…
Magnetospheric accretion models predict that matter from protoplanetary disks accretes onto the star via funnel flows which follow the stellar field lines and shock on the stellar surface leaving a hot spot with a density gradient. Previous…
We show results of global 3D MHD simulations of accretion onto stars with superposition of the dipole and octupole fields, where we vary the ratio between components. Simulations show that if octupolar field strongly dominates at the…
Determination of a magnetic field structure on a neutron star (NS) surface is an important problem of a modern astrophysics. In a presence of strong magnetic fields a thermal conductivity of a degenerate matter is anisotropic. In this paper…
We systematically examine light curves from a single hot spot on a slowly rotating neutron star with very high compactness, where the so-called invisible zone does not exist. In particular, we adopt three different shapes of hot spot and…
We discuss a number of topics relevant to disk-magnetosphere interaction and how numerical simulations illuminate them. The topics include: (1) disk-magnetosphere interaction and the problem of disk-locking; (2) the wind problem; (3)…
With the advent of space-based precision photometry missions the quantity and quality of starspot light curves has greatly increased. This paper presents a large number of starspot models and their resulting light curves to: 1) better…
Photometric observations of accreting, low-mass, pre-main-sequence stars (i.e., Classical T Tauri stars; CTTS) have revealed different categories of variability. Several of these classifications have been linked to changes in $\dot{M}$. To…
We present relativistic, radiation magnetohydrodynamic simulations of supercritical neutron star accretion columns in Cartesian geometry, including temperature-dependent, polarization-averaged Rosseland mean opacities accounting for…
We perform 2D axisymmetric radiative relativistic MHD simulations of radiation pressure supported neutron star accretion columns in split-monopole magnetic fields. The accretion columns exhibit quasi-periodic oscillations, which manifest in…
We examine the published light curves (LCs) of 117 X-ray binary pulsars, focusing on the dependence of their light curves on the observed energy bands. It is found that the energy dependence of the LCs appears only when the X-ray luminosity…
Variability observed in photometric lightcurves of late-type stars (on timescales longer than a day) is a dominant noise source in exoplanet surveys and results predominantly from surface manifestations of stellar magnetic activity, namely…
Accretion onto a highly-magnetised neutron star runs through a magnetospheric flow, where the plasma follows the magnetic field lines in the force-free regime. The flow entering the magnetosphere is accelerated by the gravity of the star…
We have developed a model of the high-energy accretion region for magnetic cataclysmic variables and applied it to {\it Extreme Ultraviolet Explorer} observations of 10 AM Herculis type systems. The major features of the EUV light curves…
High luminosity accretion onto a strongly magnetized neutron star results in a radiation pressure dominated, magnetically confined accretion column. We investigate the dynamics of these columns using two-dimensional radiative relativistic…