相关论文: Theoretical aspects of roAp stars

Three topics are discussed: 1) Photometric observations of the rapidly oscillating Ap stars have shown that the pulsation amplitude drops dramatically as a function of wavelength from the blue to the red. A theoretical derivation, plus…

This paper reviews some of the important advances made over the last decade concerning theory of roAp stars.

Some Ap stars with strong magnetic fields pulsate in high order p-modes; they are called roAp (rapidly oscillating Ap) stars. The p-mode frequencies are modified by the magnetic fields. Although the large frequency separations are hardly…

Over the last decade significant amounts of high-spectral and time-resolution spectroscopic data have been acquired for a number of rapidly oscillating Ap stars. Progress in the understanding of the information held by these data requires…

Despite more and more observational data, stellar acoustic oscillation modes are not well understood as soon as rotation cannot be treated perturbatively. In a way similar to semiclassical theory in quantum physics, we use acoustic ray…

I review recent results of the observations of magnetoacoustic p-mode oscillations in roAp stars with the focus on time-resolved spectroscopic studies. Time-series spectroscopy of roAp stars reveals unexpected and diverse pulsational…

Pulsational variability is observed in several types of main sequence stars with anomalous chemical abundances. In this contribution I summarize the relationship between pulsations and chemical peculiarities, giving special emphasis to…

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…

Magnetic perturbations to the frequencies of low degree, high radial order, axisymmetric pulsations in stellar models permeated by large scale magnetic fields are presented. Magnetic fields with dipolar, quadrupolar and a superposition of…

The mechanism for excitation of p-modes in rapidly oscillating, peculiar A (roAp, or cool chemically peculiar, CP) stars is unknown. Observations strongly suggest that acoustic modes in roAp stars are causally linked to the stars' magnetic…

Some of the rapidly oscillating (CP2) stars, have frequencies which are larger than the theoretical acoustic cut-off frequency. As the cut-off frequency depends on the T(tau) relation in the atmosphere, we have computed models and adiabatic…

I review recent theoretical work on rapidly oscillating Ap stars and discuss key aspects of the physics of the oscillations observed in this class of pulsators.

Some of the rapidly oscillating (roAp) stars, have frequencies which are larger than the theoretical acoustic cut-off frequency. We have computed models and adiabatic frequencies for pulsating Ap stars with T(tau) laws based on Kurucz model…

Peculiar A stars are so named because they exhibit abundance peculiarities in their atmospheres. It is believed that these arise as a result of differentiation of chemical species in large magnetic spots in which convective mixing is…

To answer the topical question we survey synoptically the recent literature in pulsation theory. We restrict the topics to research on roAp stars, EC 14026 variables, strange modes, luminous blue variables, pulsation-rotation coupling, and…

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…

The asteroseismology of rapidly rotating pulsating stars is hindered by our poor knowledge of the effect of the rotation on the oscillation properties. Here we present an asymptotic analysis of high-frequency acoustic modes in rapidly…

The many peculiarities of Ap stars (not only chemical ones, but also magnetic field and slow rotation) may vary during the main-sequence evolution of these stars. We review here briefly the evidences found in the last thirty years for such…

The theoretical discription of a hot star interior is obtained. It explains the distribution of stars over their masses, mass-radius-temperature and mass-luminosity dependencies. The theory of the apsidal rotation of binary stars and the…

Context. The dipole modes are the most common geometry of oscillations in roAp stars inferred from photometric measurements and are therefore of special interest for asteroseismic purposes. Aims. We present a theoretical and analytical…