Related papers: Interaction Between Convection and Pulsation
State-of-the-art one-dimensional (1D) stellar evolution codes rely on simplifying assumptions, such as mixing length theory, in order to describe superadiabatic convection. As a result, 1D stellar structure models do not correctly recover…
We have performed the first three-dimensional non-linear simulation of the turbulent convective envelope of a rotating 0.8 Msun RGB star using the ASH code. Adopting a global typical rotation rate of a tenth of the solar rate, we have…
Time-resolved spectroscopic observations of rapidly oscillating Ap (roAp) stars show a complex picture of propagating magneto-acoustic pulsation waves, with amplitude and phase strongly changing as a function of atmospheric height. We have…
Many types of stars show periodic variations of radius and brightness, which are commonly referred to as `stellar pulsations'. Observed pulsational characteristics are determined by fundamental stellar parameters. Consequently,…
Stars interact with their planets through gravitation, radiation, and magnetic fields. Although magnetic activity decreases with time, reducing associated high-energy (e.g., coronal XUV emission, flares), stellar winds persist throughout…
Tidal dissipation in stars is one of the key physical mechanisms that drive the evolution of binary and multiple stars. As in the Earth oceans, it corresponds to the resonant excitation of their eigenmodes of oscillation and their damping.…
Despite the appearance of two- and three-dimensional models thanks to the rapid growth of computing performance, numerical hydrocodes used to model radial stellar pulsations still apply a one-dimensional stellar envelope model without any…
Interaction of a stochastic background of gravitational radiation with celestial systems changes their dynamical elements in a random manner and give rise to secular changes in time. In this spirit we study the angular momentum transfer…
Pulsars are stars that emit electromagnetic radiation in well-defined time intervals. The frequency of such pulses decays with time as is quantified by the {\it braking index} ($n$). In the canonical model $n = 3$ for all pulsars, but…
High-resolution images of the solar surface show a granulation pattern of hot rising and cooler downward-sinking material -- the top of the deep-reaching solar convection zone. Convection plays a role for the thermal structure of the solar…
We study the long-term dynamics of a planetary system composed of a star and a planet. Both bodies are considered as extended, non-spherical, rotating objects. There are no assumptions made on the relative angles between the orbital angular…
Gravito-inertial waves are excited at the interface of convective and radiative regions and by the Reynolds stresses in the bulk of the convection zones of rotating stars and planets. Such waves have notable asteroseismic signatures in the…
High time resolution spectroscopy of roAp stars at large telescopes has led to a major breakthrough in our understanding of magnetoacoustic pulsations in these interesting objects. New observations have allowed to uncover a number of…
We review the derivation of the pulsations equations for spherically symmetric boson stars and then make a thorough study of the radial oscillation frequencies for the fundamental and first excited modes. We do this for self-interacting…
High-resolution spectroscopic time series of rapidly oscillating Ap stars show evidence for a co-existence of standing and running waves in their atmospheric layers. With the purpose of understanding these observations we have carried out a…
This paper reports positive detections of surface differential rotation on two rapidly rotating cool stars at several epochs, by using stellar surface features (both cool spots and magnetic regions) as tracers of the large scale latitudinal…
Context. As a star evolves, the planet orbits change with time due to tidal interactions, stellar mass losses, friction and gravitational drag forces, mass accretion and evaporation on/by the planet. Stellar rotation modifies the structure…
Scalar-tensor theories are well studied extensions of general relativity that offer deviations which are yet within observational boundaries. We present the time evolution equations governing the perturbations of a nonrotating scalarized…
The solar torsional oscillations, i.e., the perturbations of the angular velocity of rotation associated with the eleven-year activity cycle, are a manifestation of the interaction among the interior magnetic fields, amplified and modulated…
The present work investigates the numerical evolution of linearized oscillations of non-rotating, spherically symmetric neutron stars within the framework of general relativity. We derive the appropriate equations using the (3+1)-formalism.…