Related papers: Driving mechanism in massive B-type pulsators
We present results of a {\bf comprehensive} asteroseismic modelling of the $\beta$ Cephei variable $\theta$ Ophiuchi. {\bf We call these studies {\it complex asteroseismology} because our goal is to reproduce both pulsational frequencies as…
This paper reports the discovery of new slowly pulsating B-type stars. Based on the photometric, spectral, and astrometric data of TESS, LAMOST, and Gaia surveys, we have found 286 new slowly pulsating B-type stars (SPB stars) and 21…
We found the first direct evidence that the Cepheid class namesake, delta Cephei, is currently losing mass. These observations are based on data obtained with the Spitzer Space Telescope in the infrared, and with the Very Large Array in the…
We report results of our analysis of the Kepler superaperture LC data of the open cluster NGC6791 to search for pulsating sdB stars. We checked all pixels and we found only three sdB stars to be pulsating, KIC2569576 (B3), KIC2438324 (B4)…
Ap/Bp stars are magnetic chemically peculiar early A and late B type stars of the main sequence. They exhibit peculiar surface abundance anomalies that are thought to be the result of gravitational settling and radiative levitation. The…
$\beta$ Cep stars in eclipsing binary (EB) systems give us an opportunity to put observational constraints on their structure and stellar parameters. We present a comprehensive analysis of the $\beta$ Cep star in the EB V446 Cep, using…
In this paper we present a new mechanism for rationalizing, explaining and predicting pulsar glitches. Our new mechanism is based upon the concepts of type II superconductivity and the Bradlow bound.
Findings of a few recent asteroseismic studies of the main-sequence pulsating stars, as performed in Wojciech Dziembowski's group in Warsaw and in Michel Breger's group in Vienna, are briefly presented and discussed. The selected objects…
The $\beta$ Cephei pulsators are massive main-sequence stars, presenting low radial-order modes. These modes probe in particular the chemical gradient at the edge of the convective core. They hence give constraints on macroscopic processes,…
(abridged) Stars spend most of their life on the main sequence (MS). But their most substantial changes occur off the MS stage, either before on the pre-MS or beyond at the post-MS phase. Due to very complex and varied dynamical processes,…
We propose a new neutrino propulsion mechanism for neutron stars which can lead to strong velocity kicks, needed to explain the observed bimodal velocity distribution of pulsars. The spatial asymmetry in the neutrino emission is naturally…
We speculate that stationary force-free pulsar magnetospheres are screw unstable, and the spin-down power of real pulsars is carried by turbulent Poynting jets. The turbulent jet entrains poloidal flux as it propagates away from the star.…
Developments of this far-reaching research field are summarized from an observational point of view, mentioning important and interesting phenomena discovered recently by photometry of stellar oscillations of any kind. A special emphasis is…
High-mass binary stars are known to show an unexplained discrepancy between the dynamical masses of the individual components and those predicted by models. In this work, we study Sigma Scorpii, a double-lined spectroscopic binary system…
As many as 10\% of OB-type stars have global magnetic fields, which is surprising given their internal structure is radiative near the surface. A direct probe of internal structure is pulsations, and some OB-type stars exhibit pressure…
The recently discovered new class of sdB pulsators (sdBV) offers a powerful possibility for the investigation of their interior and thus their evolutionary history. The first step towards applying asteroseismologic tools is the…
Horizontal branch stars should show significant differential rotation with depth. Models that assume systematic angular momentum exchange in the convective envelope and local conservation of angular momentum in the core produce HB models…
After a brief introduction into the asteroseismic modelling of stars, we provide a compilation of the current seismic estimates of the core overshooting parameter and of the rotational frequency of single and binary massive stars. These…
The region in the HR-diagram where the main sequence intersects the classical instability strip hosts A- and F-type stars exhibiting a rich variety of physical phenomena, such as pulsations on various time scales and chemical peculiarities.…
Random changes in pulsation period occur in cool pulsating Mira variables, Type A, B, and C semiregular variables, RV Tauri variables, and in most classical Cepheids. The physical processes responsible for such fluctuations are uncertain,…