相关论文: Mode Switching Time Scales in the Classical Variab…
Small cyclic variations in the frequencies of acoustic modes are expected to be a common phenomenon in solar-like pulsators, as a result of stellar magnetic activity cycles. The frequency variations observed throughout the solar and stellar…
The standard theory of pulsations deals with the frequencies and growth rates of infinitesimal perturbations in a stellar model. Modes which are calculated to be linearly driven should increase their amplitudes exponentially with time; the…
We briefly review the main problems related to the computation of the evolution of intermediate-mass stars: the treatment of turbulent convection and the occurrence of blue loops during the core He-burning phase. It is shown that, in order…
In most Delta Scuti stars, the measured period changes are considerably larger than those expected from stellar evolution. In order to study these period and amplitude changes, a few selected stars are measured photometrically for hundreds…
Stellar evolution theory predicts that asymptotic giant branch stars undergo a series of short thermal pulses that significantly change their luminosity and mass on timescales of hundreds to thousands of years. Secular changes in these…
Theoretical estimates of the pulsation period change rates in LMC Cepheids are obtained from consistent calculation of stellar evolution and nonlinear stellar pulsation for stars with initial chemical composition X=0.7, Z=0.008, initial…
In this paper we present calculations of period distribution for old accreting isolated neutron stars (INSs). At the age about a few billions years low velocity INSs come to the stage of accretion. At that stage their period evolution is…
We show that density fluctuations during phase transitions in pulsar cores may have non-trivial effects on pulsar timings, and may also possibly account for glitches and anti-glitches. These density fluctuations invariably lead to non-zero…
The rate of metastable decay in nonequilibrium systems is expected to display scaling behavior: i.e., the logarithm of the decay rate should scale as a power of the distance to a bifurcation point where the metastable state disappears.…
A comparison of the hot and cool boundaries of the classical instability strip with observations has been an important test for stellar structure and evolution models of post- and main sequence stars. Over the last few years, the number of…
We discuss the role of differential rotation in the evolution of the l=2 r-mode instability of a newly born, hot, rapidly-rotating neutron star. It is shown that the amplitude of the r-mode saturates in a natural way at a value that depends…
In recent years, ground- and space-based photometric surveys have characterized the rotational evolution of solar-like stars to an unprecedented level of detail. In this work we focus on the slow-rotator sequence, an emergent feature…
The dynamical shear instability is an important mixing process in the advanced stages of the evolution of massive stars. We calculated different models of 15 Mo with an initial rotational velocity, v(rot,ini)= 300 km/s to investigate its…
We investigate whether angular momentum transport due to unstable pulsation modes can play a significant role in the rotational evolution of massive stars. We find that these modes can redistribute appreciable angular momentum, and moreover…
Z Cam variables are a subclass of dwarf nova that lie near a global bifurcation between outbursting ("limit cycle") and non-outbursting ("standstill") states. It is believed that variations in the secondary star's mass-injection rate…
For a number of starless cores, self-absorbed molecular line and column density observations have implied the presence of large-amplitude oscillations. We examine the consequences of these oscillations on the evolution of the cores and the…
Species diversity in ecosystems is often accompanied by the self-organisation of the population into fascinating spatio-temporal patterns. Here, we consider a two-dimensional three-species population model and study the spiralling patterns…
Elastic strips provide a canonical system for studying the mechanisms governing elastic shape transitions. Buckling, linear snap-through, and nonlinear snap-through have been observed in boundary-actuated strips and linked to the type of…
Context. Considerable effort has been put into using light curves observed by space telescopes such as CoRoT, Kepler and TESS for determining stellar rotation periods. While rotation periods of active stars can be reliably determined, the…
Many planets are observed in stellar binary systems, and their frequency may be comparable to that of planetary systems around single stars. Binary stellar evolution in such systems influences the dynamical evolution of the resident…