Related papers: Oscillatory secular modes: The thermal micropulses
Variability and mass-loss are common phenomena in massive OB-type stars. It is argued that they are caused by violent strange mode instabilities identified in corresponding stellar models. We present a systematic linear stability analysis…
We study the dynamics of phase transitions in the interstellar medium by means of three-dimensional hydrodynamic numerical simulations. We use a realistic cooling function and generic nonequilibrium initial conditions to follow the…
To model the temperature evolution of optically thin astrophysical environments at MHD scales, radiative and collisional cooling rates are typically either pre-tabulated or fit into a functional form and then input into MHD codes as a…
Using linear non-adabatic pulsation analysis, we explore the radial-mode (p-mode) stability of stars across a wide range of mass (0.2 <= M <= 50 Msun), composition (0 <= X <= 0.7, Z=0.001, 0.02), effective temperature (3 000 <= T_eff <= 40…
Thermonuclear burning on the surface of accreting neutron stars is observed to stabilize at accretion rates almost an order of magnitude lower than theoretical models predict. One way to resolve this discrepancy is by including a base…
An overview of selected topical problems on modelling oscillation properties in solar-like stars is presented. High-quality oscillation data from both space-borne intensity observations and ground-based spectroscopic measurements provide…
The thermal stability of rotating, stratified, unmagnetized atmospheres is studied by means of linear-perturbation analysis, finding stability, overstability or instability, depending on the properties of the gas distribution, but also on…
The thermal stability of a weakly magnetized, rotating, stratified, optically thin plasma is studied by means of linear-perturbation analysis. We derive dispersion relations and criteria for stability against axisymmetric perturbations that…
The thermal instability with a piecewise power law cooling function is investigated using one- and three-dimensional simulations with periodic and shearing-periodic boundary conditions in the presence of constant thermal diffusion and…
We investigate the evolutionary behavior of stellar structures with metallicity Z=0.04 in order to disclose theoretical expectations for both evolutionary and pulsational behaviors of Super-Metal-Rich (SMR) objects, which are found in the…
We have performed a linear pulsational stability survey of 6 series of long period variable models with M=1.0 Msun, L=3000 - 8000Lsun, and (X,Z)= (0.700,0.020),(0.735,0.005). The dynamic and thermodynamic couplings between convection and…
Stellar spectra with a high resolution of 115000 obtained with the HARPS spectrograph provide an opportunity to examine turbulence velocities and their depth distributions in the photosphere of stars. Fourier analysis was performed for 17…
We consider the thermal properties of cold, dense clouds of molecular hydrogen and atomic helium. For cloud masses below 10^-1.7 Msun, the internal pressure is sufficient to permit the existence of particles of solid or liquid hydrogen at…
There is evidence that coronal heating is highly intermittent, and flares are the high energy extreme. The properties of the heat pulses are difficult to constrain. Here hydrodynamic loop modeling shows that several large amplitude…
We discovered an oscillatory instability in a system of inelastically colliding hard spheres, driven by two opposite "thermal" walls at zero gravity. The instability, predicted by a linear stability analysis of the equations of granular…
Thermal pulses are fundamental to the chemical evolution of AGB stars and their circumstellar envelopes. A further consequence of thermal pulses is the formation of detached shells of gas and dust around the star. We aim to determine the…
We conduct two kinds of homogeneous isotropic turbulence simulations relevant for the intracluster medium (ICM): (i) pure turbulence runs without radiative cooling; (ii) turbulent heating$+$radiative cooling runs with global thermal…
Black Saturns have multiple horizons and so offer a testing ground for the ideas of black hole thermodynamics. In this note, we numerically scan for phases that are in equilibrium by extremizing total entropy in the 2-dimensional moduli…
Most aspects of stellar evolution proceed far too slowly to be directly observable in a single star on human timescales. The thermally pulsing asymptotic giant branch is one exception. The combination of state-of-the-art modelling…
Material accreted onto a neutron star can stably burn in steady state only when the accretion rate is high (typically super-Eddington) or if a large flux from the neutron star crust permeates the outer atmosphere. For such situations we…